Azo pigments, process for producing the azo pigments, and pigment dispersion, coloring composition and ink for inkjet recording containing the pigment

ABSTRACT

An azo pigment represented by the following general formula (1), a tautomer of the azo pigment, and a salt or a hydrate thereof: 
     
       
         
         
             
             
         
       
         
         
           
             wherein each of R 1 , R 2 , P 1 , P 2 , Q 1 , and Q 2  independently represents a hydrogen atom or a substituent, G represents the non-metallic atoms necessary to complete a 5- to 6-membered heterocyclic group, W represents a substituent capable of binding to the heterocyclic group constituted by G, t represents an integer of from 0 to 4, each of Het-1 and Het-2 independently represents a group selected from specific aromatic heterocyclic groups.

TECHNICAL FIELD

The present invention relates to azo pigments and a process forproducing them, and a pigment dispersion, coloring composition and inkfor inkjet recording containing the pigment.

BACKGROUND ART

In recent years, as image-recording materials, materials for formingcolor images have been main and, specifically, recording materials foran ink jet system, recording materials for a thermal transfer system,recording materials for an electrophotographic system, transfer typesilver halide light-sensitive materials, printing inks, and recordingpens have found widespread use. Also, in photographing devices such asCCDs for photographing equipment, and in LCDs and PDPs for display,color filters are used for recording or reproducing a color image. Inthese color image recording materials and color filters, colorants (dyesor pigments) of three primary colors of a so-called additive colormixing process or subtractive color mixing process have been used inorder to display or record full-color images. In actuality, however,there is no fast colorant having the absorption characteristics capableof realizing a preferred color reproduction region and resisting varioususe conditions and environmental conditions. Thus, the improvementthereof has strongly been desired.

In particular, use of recording materials has extended from domestic useto industrial use and, as a result, they are required to haveperformance at a higher level (regarding hue, coloring strength, andimage fastness to light, gas, heat, moisture, and chemicals).

With respect to coloring materials to be used (for example, an ink forinkjet recording), dye inks are required to be changed fromwater-soluble inks to oil-soluble inks and, in the case where a muchhigher level of performance is required (from indoor use to outdooruse), the inks are required to be changed from dye inks to pigment inks.

Difference between dyes and pigments in using manner is that, while dyesare used in a state of being dissolved (a state of molecular dispersion)in a medium such as fibers or solvents, pigments are used in a state ofsolid particles (molecular aggregate) finely dispersed in a mediumwithout being dissolved.

The dyes or pigments to be used for the above-mentioned uses arerequired to have in common the following properties. That is, they arerequired to have absorption characteristics favorable in view of colorreproduction and have good fastness under the conditions of theenvironment wherein they are used, for example, fastness against light,heat, and an oxidative gas such as ozone. In addition, in the case wherethe colorant is a pigment, the pigment is further required to besubstantially insoluble in water or in an organic solvent, to have agood fastness to chemicals, and not to lose the preferred absorptioncharacteristics it shows in a molecularly dispersed state even when usedas particles. Although the required properties described above can becontrolled by adjusting the intensity of intermolecular mutual action,both of them are in a trade-off relation with each other, thus beingdifficult to allow them to be compatible with each other.

Besides, in the case of using a pigment as the colorant, the pigment isadditionally required to have a particle size and a particle shapenecessary for realizing desired transparency or masking properties, tohave good fastness under the conditions of the environment wherein theyare used, for example, fastness against light, heat, and an oxidativegas such as ozone, to have good fastness to an organic solvent andchemicals such as a sulfurous acid gas, and to be capable of beingdispersed in a used medium to a level of fine particles, with thedispersed state being stable. These properties are largely influenced bythe particle size, particle shape, and crystallinity as well as thechemical structure thereof, and hence it is of extreme importance tocontrol them (see, for example, JP-A-2004-26930). In particular, thereis a strong demand for a pigment which has a good yellow hue and is fastto light, moist heat, and active gases in the environment, especially apigment which has a high coloring ability and a fastness to light.

That is, in comparison with a dye which is required to have propertiesas dye molecules, the pigment is required to have more properties, i.e.,it is required to satisfy all of the above-mentioned requirements as asolid of an aggregate of a colorant (dispersion of fine particles) aswell as the properties as molecules of a coloring material. As a result,a group of compounds which can be used as pigments are extremely limitedin comparison with dyes. Even when high-performance dyes are convertedto pigments, few of them can satisfy requirement for the properties as adispersion of fine particles. Thus, such pigments are difficult todevelop. This can be confirmed from the fact that the number of pigmentsregistered in Color Index is no more than 1/10 of the number of dyes.

Azo pigments are excellent in hue and coloring ability which arecharacteristics of coloring, and hence they have widely been used inprinting inks, inks for an ink jet system, and electrophotographicmaterials. Of the pigments, diarylide pigments are the most typicallyused yellow azo pigments. Examples of such diarylide pigments includeC.I. pigment yellow 12, C.I. pigment yellow 13, and C.I. pigment yellow17. However, the diarylide pigments are inferior in fastness,particularly light fastness, and hence they are decomposed when printsprinted by them are exposed to light, thus being inappropriate forprints which are to be stored for a long time.

In order to remove such defects, there have been disclosed azo pigmentshaving a fastness improved by increasing molecular weight or byintroducing a group having a strong intermolecular mutual action (see,for example JP-A-56-38354, U.S. Pat. No. 2,936,306, and JP-A-11-100519).However, even the improved pigments, for example, the pigments describedin JP-A-2004-26930 have the defect that they have still insufficientlight fastness though improved to some extent, and pigments describedin, for example, U.S. Pat. No. 2,936,306 and JP-A-11-100519 have agreenish hue and a low coloring ability, thus being inferior in coloringcharacteristics.

Also, JP-A-2003-277662 discloses colorants which have absorptioncharacteristics of excellent color reproducibility and has a sufficientfastness. However, all of the specific compounds described inJP-A-2003-277662 are soluble in water or in an organic solvent, thusbeing insufficient in fastness to chemicals.

By the way, U.S. Pat. No. 7,125,446 describes an example wherein acolorant of dye is dissolved in a water medium to use it as awater-soluble ink for use in inkjet recording. Also, JP-A No. 61-36362describes examples of anion type monoazo compounds having characteristiclight fastness. However, the level of image fastness provided by theseexamples is not sufficient for satisfying requirements for colorants athigh level, and they fail to provide manners of using pigments.

In the case of expressing a full-color image based on the subtractivecolor mixing process using three colors of yellow, magenta, and cyan orusing four colors further including black, use of a pigment having aninferior fastness as a yellow pigment, gray balance of the prints wouldbe changed with the lapse of time, and use of a pigment having inferiorcoloring characteristics would reduce color reproducibility uponprinting. Thus, in order to obtain prints which can maintain high colorreproducibility for a long time, there have been desired a yellowpigment and a pigment dispersion which have both good coloringcharacteristics and good fastness.

Also, Japanese Patent No. 4,073,453 discloses colorants of dyes havingabsorption characteristics excellent in color reproducibility and havingan extremely high level fastness.

However, all of the specific compounds described in Japanese Patent No.4,073,453 have such a high solubility in water or an organic solventthat, when used as pigments, an intended dispersion of pigment fineparticles is not obtained, with a colorant solution or emulsion beingprovided. As a result, it has been difficult to use them as a coloringmaterial containing a pigment dispersion with the purpose of impartingvarious required performances at high levels.

DISCLOSURE OF THE INVENTION

The invention provides azo pigments having excellent coloringcharacteristics such as coloring ability and hue and having excellentdurability such as light fastness and resistance to ozone, a process forproducing the pigments, a dispersion of the pigment, a coloringcomposition, and an ink for ink jet recording. As a result of intensiveinvestigations in consideration of the above-mentioned circumstances,the inventors have obtained novel azo pigments and have found that theyhave both excellent coloring characteristics and excellent durability,thus having completed the invention.

That is, the invention is as follows.

<1> An azo pigment represented by the following general formula (1), atautomer of the azo pigment, and a salt or a hydrate thereof:

wherein

each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents a hydrogenatom or a substituent,

G represents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group,

W represents a substituent capable of binding to the heterocyclic groupconstituted by G,

t represents an integer of from 0 to 4,

each of Het-1 and Het-2 independently represents a group selected fromthe aromatic heterocyclic groups represented by the following generalformula (2):

wherein

each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄ independently represents ahydrogen atom or a substituent, and

* shows the point of attachment to the azo linkage in the generalformula (1).

<2> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to <1>, wherein

the azo pigment is represented by the following general formula (3):

wherein

each of R₁ and R₂ independently represents a hydrogen atom or asubstituent,

G represents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group,

W represents a substituent capable of binding to the heterocyclic groupconstituted by G,

t represents an integer of from 0 to 4,

each of Het-1 and Het-2 independently represents a group selected fromaromatic heterocyclic groups represented by the general formula (2),provided that * in the general formula (2) shows the point of attachmentto the azo linkage in the general formula (3).

<3> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to <1> or <2>, wherein

the azo pigment is represented by the following general formula (4):

wherein

each of R₁ and R₂ independently represents a hydrogen atom or asubstituent,

each of X₁ and X₂ independently represents an electron-withdrawing grouphaving a Hammett's σp value of 0.2 or more,

each of Y₁, Y₂, Z₁, and Z₂ independently represents a hydrogen atom or asubstituent,

G represents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group,

W represents a substituent capable of binding to the heterocyclic groupconstituted by G, and

t represents an integer of from 0 to 4.

<4> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to <1> or <2>, wherein

the azo pigment is represented by the following general formula (5):

wherein

each of R₁ and R₂ independently represents a hydrogen atom or asubstituent,

each of Het-1 and Het-2 independently represents a group selected fromthe aromatic heterocyclic groups represented by the general formula (2),provided that * in the general formula (2) shows the point of attachmentto the azo linkage in the general formula (5), and

W represents a substituent on the s-triazinyl group.

<5> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to any one of <1>, <2> and <4>, wherein

the azo pigment is represented by the following general formula (6):

wherein

each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, and

each of Het-1 and Het-2 independently represents a group selected fromthe aromatic heterocyclic groups represented by the general formula (2),provided that * in the general formula (2) shows the point of attachmentto the azo linkage in the general formula (6).

<6> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to any one of <1>, <2>, <4> and <5>, wherein

the tautomer of the azo pigment is represented by any one of thefollowing general formulae (6′) to (6′″):

wherein

each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, and

-   -   each of Het-1 and Het-2 independently represents a group        selected from the aromatic heterocyclic groups represented by        the general formula (2), provided that * in the general        formula (2) shows the point of attachment to the azo linkage in        the general formulae (6′) to (6′″).        <7> The azo pigment, the tautomer of the azo pigment, and the        salt or hydrate thereof according to any one of <1> to <6>,        wherein

the azo pigment has a peak absorption intensity in the range of from1700 to 1730 cm⁻¹ in the IR absorption spectrum which is 1/3 or less ofa peak absorption intensity in the range of from 1620 to 1670 cm⁻¹.

<8> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to any one of <1> to <3>, wherein

the azo pigment is represented by the following general formula (7):

wherein

each of R₁ and R₂ independently represents a hydrogen atom or asubstituent,

each of X₁ and X₂ independently represents an electron-withdrawing grouphaving a Hammett's σp value of 0.2 or more,

each of Y₁, and Y₂ independently represents a hydrogen atom or asubstituent,

G₁ represents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group,

W represents a substituent capable of binding to the heterocyclic groupconstituted by G₁,

t represents an integer of from 0 to 4,

each of G₁₁ and G₁₂ independently represents the non-metallic atomgroups necessary to complete a 5- to 6-membered heterocyclic group,provided that each of the heterocyclic groups represented by G₁₁ and G₁₂may independently be unsubstituted or may have a substituent, and may bea monocyclic ring or may have a condensed ring.

<9> The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to <8>, wherein

at least one of the nitrogen-containing heterocyclic groups respectivelyrepresented by G_(1l) and G₁₂ is represented by any one of (G-1) to(G-13) in the following general formula (8):

wherein

* in (G-1) to (G-13) shows the point of attachment to the N atom on thepyrazole ring in the general formula (7),

each of Z₁₁ to Z₁₄ represents a substituent capable of binding to theheterocyclic group, and

G′ in (G-13) represents the non-metallic atoms necessary to complete aheterocyclic group.

<10> A process for producing the azo pigment described in any one of <1>to <9>, comprising:

preparing a diazonium compound by diazotization of a heterocyclic aminerepresented by the following general formula (9),

dissolving a compound represented by the following formula (11) in anorganic solvent, and

coupling the diazonium compound and the compound represented by thegeneral formula (11) after the dissolution of the compound representedby the general formula (11):

Het.-NH₂  General formula (9)

wherein

Het. represents a heterocyclic group selected from aromatic heterocyclicgroups represented by the following general formula (10):

wherein

each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄ independently represents ahydrogen atom or a substituent, and

* shows the point of attachment to the amino group in the generalformula (9):

wherein

each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents a hydrogenatom or a substituent,

G represents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group,

W represents a substituent capable of binding to the heterocyclic groupconstituted by G, and

t represents an integer of from 0 to 4.

<11> A process for producing the azo pigment described in any one of <1>to <9>, comprising:

preparing a diazonium compound by diazotization of a heterocyclic aminerepresented by the following general formula (9),

coupling the diazonium compound and a compound represented by thefollowing general formula (11) in the presence of a polar aproticsolvent:

Het.-NH₂  General formula (9)

wherein

Het. represents a heterocyclic group selected from aromatic heterocyclicgroups represented by the following general formula (10):

wherein

each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄ independently represents ahydrogen atom or a substituent, and

* shows the point of attachment to the amino group in the generalformula (9):

wherein

each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents a hydrogenatom or a substituent,

G represents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group,

W represents a substituent capable of binding to the heterocyclic groupconstituted by G, and

t represents an integer of from 0 to 4.

<12> The azo pigment according to any one of claims 1 to 9, which isobtained by the process described in <10> or <11>.<13> A pigment dispersion comprising:

at least one of the azo pigment, the tautomer of the azo pigment, andthe salt or hydrate thereof described in any one of <1> to <9> and <12>.

<14> A coloring composition comprising:

at least one of the azo pigment, the tautomer of the azo pigment, andthe salt or hydrate thereof described in any one of <1> to <9> and <12>.

<15> An ink for inkjet recording, comprising:

at least one of the azo pigment, the tautomer of the azo pigment, andthe salt or hydrate thereof described in any one of <1> to <9> and <12>.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows the infrared absorption spectrum of the azo pigment (Pig-1)synthesized according to Example 1;

FIG. 2 shows the infrared absorption spectrum of the azo pigment (Pig-2)synthesized according to Example 2;

FIG. 3 shows the infrared absorption spectrum of the azo pigment (Pig-4)synthesized according to Example 3;

FIG. 4 shows the infrared absorption spectrum of the azo pigment (Pig-7)synthesized according to Example 4;

FIG. 5 shows the infrared absorption spectrum of the azo pigment(Pig-27) synthesized according to Example 5;

FIG. 6 shows the infrared absorption spectrum of the azo pigment(Pig-47) synthesized according to Example 6;

FIG. 7 shows the infrared absorption spectrum of the azo pigment (Pig-9)synthesized according to Example 7;

FIG. 8 shows the infrared absorption spectrum of the azo pigment(Pig-11) synthesized according to Example 8;

FIG. 9 shows the infrared absorption spectrum of the azo pigment(Pig-12) synthesized according to Example 9;

FIG. 10 shows the infrared absorption spectrum of the azo pigment(Pig-13) synthesized according to Example 10;

FIG. 11 shows the infrared absorption spectrum of the azo pigment(Pig-16) synthesized according to Example 11;

FIG. 12 shows the infrared absorption spectrum of the azo pigment(Pig-25) synthesized according to Example 12;

FIG. 13 shows the infrared absorption spectrum of the azo pigment(Pig-28) synthesized according to Example 13;

FIG. 14 shows the infrared absorption spectrum of the azo pigment(Pig-29) synthesized according to Example 14;

FIG. 15 shows the infrared absorption spectrum of the azo pigment(Pig-30) synthesized according to Example 15;

FIG. 16 shows the infrared absorption spectrum of the azo pigment(Pig-31) synthesized according to Example 16;

FIG. 17 shows the infrared absorption spectrum of the azo pigment(Pig-32) synthesized according to Example 17;

FIG. 18 shows the infrared absorption spectrum of the azo pigment(Pig-37) synthesized according to Example 18;

FIG. 19 shows the infrared absorption spectrum of the azo pigment(Pig-39) synthesized according to Example 19;

FIG. 20 shows the infrared absorption spectrum of the azo pigment(Pig-41) synthesized according to Example 20;

FIG. 21 shows the infrared absorption spectrum of the azo pigment(Pig-42) synthesized according to Example 21;

FIG. 22 shows the infrared absorption spectrum of the azo pigment(Pig-43) synthesized according to Example 22;

FIG. 23 shows the infrared absorption spectrum of the azo pigment(Pig-44) synthesized according to Example 23;

FIG. 24 shows the infrared absorption spectrum of the azo pigment(Pig-45) synthesized according to Example 24;

FIG. 25 shows the infrared absorption spectrum of the azo pigment(Pig-46) synthesized according to Example 25;

FIG. 26 shows the infrared absorption spectrum of the azo pigment(Pig-49) synthesized according to Example 26;

FIG. 27 shows the infrared absorption spectrum of the azo pigment(Pig-51) synthesized according to Example 27;

FIG. 28 shows the infrared absorption spectrum of the azo pigment(Pig-52) synthesized according to Example 28;

FIG. 29 shows the infrared absorption spectrum of the azo pigment(Pig-53) synthesized according to Example 29;

FIG. 30 shows the infrared absorption spectrum of the azo pigment(Pig-54) synthesized according to Example 30; and

FIG. 31 shows the infrared absorption spectrum of the azo pigment(Pig-59) synthesized according to Example 31.

BEST MODE FOR CARRYING OUT THE INVENTION

The invention will be described in detail below.

The Hammett substituent constant σp used in this specification will bedescribed here. Hammett's rule is an empirical rule propounded by L. P.Hammett in 1935 in order to quantitatively deal with the influence of asubstituent on the reaction and equilibrium of a benzene derivative, andthe validity thereof has today been widely recognized. As thesubstituent constants determined in Hammett's rule, there are the σpvalue and the am value. These constants are described in detail, forexample, in Lange's Handbook of Chemistry, the 12th edition, edited byJ. A. Dean, 1979 (McGraw-Hill) and Kagaku no Ryoiki (Journal of JapaneseChemistry), an extra issue, 122, 96-103 (1979), Nankodo, although theycan be found in many general literatures. In the invention, eachsubstituent is limited or described by the Hammett substituent constantσp. However, this does not mean that the substituent is limited to onlya substituent having the constant known in the above-mentioned generalliteratures. Even when the constant is unknown in literatures, it goeswithout saying that a substituent having the constant that will bewithin the range when measured based on Hammett's rule is also included.Further, although the compounds of the invention represented by thegeneral formulae (1) to (12) are not the benzene derivatives, the σpvalue is used as a measure indicating the electronic efficiency of thesubstituent, independently of the substituted position. In theinvention, the σp value is used hereinafter in such a sense.

[Azo Pigments]

The azo pigments in the invention are represented by the foregoinggeneral formula (1). The compounds represented by the general formula(1) have a low solubility in water, an organic solvent or the likebecause of the specific structure thereof, and thus they can be used asazo pigments. Pigments are used in a state of solid particles such asmolecular aggregates finely dispersed in a solvent, unlike dyes whichare used in a state of molecular dispersion dissolved in water, anorganic solvent or the like.

The azo pigments represented by the general formula (1), the tautomersthereof, and the salts or hydrates thereof will be described in detailbelow.

(In the general formula (1), each of R₁, R₂, P₁, P₂, Q₁, and Q₂independently represents a hydrogen atom or a substituent, G representsthe non-metallic atoms necessary to complete a 5- to 6-memberedheterocyclic group, W represents a substituent capable of binding to theheterocyclic group constituted by G, t represents an integer of from 0to 4, each of Het-1 and Het-2 independently represents a group selectedfrom the aromatic heterocyclic groups represented by the followinggeneral formula (2) (wherein * shows the point of attachment to the azolinkage in the general formula (1)):

(in the general formula (2), each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄independently represents a hydrogen atom or a substituent).

The general formula (1) will be described in more detail below.

In the general formula (1), the heterocyclic group represented by Het-1or Het-2 represents a group selected from the aromatic heterocyclicgroups represented by the above general formula (2), and substituents onthe hetero ring may further bind to each other to form a condensed ring.The asterisk * shows the point of attachment to the azo linkage in thegeneral formula (1).

As examples of the heterocyclic group, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are more preferred, (2), (5), (6), (7), and (10) areparticularly preferred, (2) and (7) are still more preferred, and (2) ismost preferred.

X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the general formula (2) independentlyrepresents a hydrogen atom or a substituent.

Examples of the substituent represented by X, Y, Z, W₀, W₁, W₂, W₃, orW₄ include a straight or branched alkyl group containing from 1 to 12carbon atoms, a straight or branched aralkyl group containing from 7 to18 carbon atoms, a straight or branched alkenyl group containing from 2to 12 carbon atoms, a straight or branched alkynyl group containing from2 to 12 carbon atoms, a straight or branched cycloalkyl group containingfrom 3 to 12 carbon atoms, a straight or branched cycloalkenyl groupcontaining from 3 to 12 carbon atoms (for example, methyl, ethyl,n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, 2-ethylhexyl,2-methylsulfonylethyl, 3-phenoxypropyl, trifluoromethyl or cyclopentyl),a halogen atom (for example, a chlorine atom or a bromine atom), an arylgroup (for example, phenyl, 4-t-butylphenyl or 2,4-di-t-amylphenyl), aheterocyclic group (for example, imidazolynyl, pyrazolinyl, triazolinyl,2-furyl, 2-thienyl, 2-pyrimidyl or 2-benzothiazolinyl), a cyano group, ahydroxyl group, a nitro group, a carboxy group, an amino group, analkyloxy group (for example, methoxy, ethoxy, 2-methoxyethoxy or2-methylsulfonylethoxy), an aryloxy group (for example, phenoxy,2-methylphenoxy, 4-t-butylphenoxy, 3-nitrophenoxy,3-t-butyloxycarbonylphenoxy or 3-methoxycarbonylphenyloxy), an acylaminogroup (for example, acetamido, benzoamido or4-(3-t-butyl-4-hydroxyphenoxy)butanamido), an alkylamino group (forexample, methylamino, butylamino, diethylamino or methylbutylamino), anarylamino group (for example, phenylamino or 2-chloroanilino), an ureidogroup (for example, phenylureido, methylureido or N,N-dibutylureido), asulfamoylamino group (for example, N,N-dipropylsulfamoylamino), analkylthio group (for example, methylthio, octylthio or2-phenoxyethylthio), an arylthio group (for example, phenylthio,2-butoxy-5-t-octylphenylthio or 2-carboxyphenylthio), analkyloxycarbonylamino group (for example, methoxycarbonylamino), analkylsulfonylamino group and an arylsulfonylamino group (for example,methylsulfonylamino, phenylsulfonylamino or p-toluenesulfonylamino), acarbamoyl group (for example, N-ethylcarbamoyl or N,N-dibutylcarbamoyl),a sulfamoyl group (for example, N-ethylsulfamoyl, N,N-dipropylsulfamoylor N-phenylsulfamoyl), a sulfonyl group (for example, methylsulfonyl,octylsulfonyl, phenylsulfonyl or p-toluenesulfonyl), an alkyloxycarbonylgroup (for example, methoxycarbonyl or butyloxycarbonyl), a heterocyclicoxy group (for example, 1-phenyltetrazol-5-oxy or2-tetrahydropyranyloxy), an azo group (for example, phenylazo,4-methoxyphenylazo, 4-pivaloylaminophenylazo or2-hydroxy-4-propanoylphenylazo), an acyloxy group (for example,acetoxy), a carbamoyloxy group (for example, n-methylcarbamoyloxy orN-phenylcarbamoyloxy), a silyloxy group (for example, trimethylsilyloxyor dibutylmethylsilyloxy), an aryloxycarbonylamino group (for example,phenoxycarbonylamino), an imido group (for example, N-succinimido orN-phthalimido), a heterocyclic thio group (for example,2-benzothiazolylthio, 2,4-di-phenoxy-1,3,5-triazol-6-thio or2-pyridylthio), a sulfinyl group (for example, 3-phenoxypropylsulfinyl),a phosphonyl group (for example, phenoxyphosphonyl, octyloxyphosphonylor phenylsulfonyl), an aryloxycarbonyl group (for example,phenoxycarbonyl), an acyl group (for example, acetyl, 3-phenylpropanoylor benzoyl), and an ionic hydrophilic group (for example, a carboxylgroup, a sulfo group, a phosphono group or a quaternary ammonium group).

In the case where the azo pigment of the invention contains the ionichydrophilic group as a substituent, the pigment is preferably a saltwith a polyvalent metal cation (for example, magnesium, calcium orbarium), and is particularly preferably a lake pigment.

In the general formula (2), preferred examples of each of thesubstituents of X and W₀ are independently electron-withdrawing groups,particularly electron-withdrawing groups having a Hammett substituentconstant σp value of 0.20 or more, more preferably electron-withdrawinggroups having a Hammett substituent constant σp value of 0.30 or more,with 1.0 being the upper limit.

Specific examples of the electron-withdrawing group having a σp value of0.20 or more include an acyl group, an acyloxy group, a carbamoyl group,an alkyloxycarbonyl group, an aryloxycarbonyl group, a cyano group, anitro group, a dialkylphosphono group, a diarylphosphono group, adiarylphosphinyl group, an alkylsulfinyl group, an arylsulfinyl group,an alkylsulfonyl group, an arylsulfonyl group, a sulfonyloxy group, anacylthio group, a sulfamoyl group, a thiocyanato group, a thiocarbonylgroup, a halogenated alkyl group, a halogenated alkoxy group, ahalogenated aryloxy group, a halogenated alkylamino group, a halogenatedalkylthio group, an aryl group substituted by other electron-withdrawinggroup having a σp value of 0.20 or more, a heterocyclic group, a halogenatom, an azo group or a selenocyanato group.

As preferred examples of each of the substituents of X and W₀, there areindependently illustrated an acyl group containing from 2 to 12 carbonatoms, anacyloxy group containing from 2 to 12 carbon atoms, a carbamoylgroup containing from 1 to 12 carbon atoms, an alkyloxycarbonyl groupcontaining from 2 to 12 carbon atoms, an aryloxycarbonyl groupcontaining from 7 to 18 carbon atoms, a cyano group, a nitro group, analkylsulfinyl group containing from 1 to 12 carbon atoms, anarylsulfinyl group containing from 6 to 18 carbon atoms, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, a sulfamoylgroup containing from 0 to 12 carbon atoms, a halogenated alkyl groupcontaining from 1 to 12 carbon atoms, a halogenated alkyloxy groupcontaining from 1 to 12 carbon atoms, a halogenated alkylthio groupcontaining from 1 to 12 carbon atoms, a halogenated aryloxy groupcontaining from 7 to 18 carbon atoms, an aryl group containing from 7 to18 carbon atoms and being substituted by two or more otherelectron-withdrawing groups having a σp value of 0.20 or more, and a 5-to 8-membered heterocyclic group containing a nitrogen atom, an oxygenatom or a sulfur atom and containing from 1 to 18 carbon atoms.

More preferred are a cyano group, an alkylsulfonyl group containing from1 to 12 carbon atoms, an arylsulfonyl group containing from 6 to 18carbon atoms and a sulfamoyl group containing from 0 to 12 carbon atoms.Particularly preferred are a cyano group, an alkylsulfonyl groupcontaining from 1 to 8 carbon atoms, an arylsulfonyl group containingfrom 6 to 12 carbon atoms, and a sulfamoyl group containing from 0 to 8carbon atoms. Among them, a cyano group, a methanesulfonyl group, aphenylsulfonyl group and a sulfamoyl group are preferred, a cyano groupand a methanesulfonyl group are still more preferred, and a cyano groupis the most preferred.

Preferred examples of Z in the general formula (2) are a hydrogen atom,a substituted or unsubstituted alkyl group, a substituted orunsubstituted cycloalkyl group, a substituted or unsubstituted alkenylgroup, a substituted or unsubstituted alkynyl group, a substituted orunsubstituted aralkyl group, a substituted or unsubstituted aryl group,a substituted or unsubstituted heterocyclic group, a substituted orunsubstituted alkylsulfonyl group, a substituted or unsubstitutedarylsulfonyl group, and an acyl group. Particularly preferredsubstituents are a substituted or unsubstituted aryl group, asubstituted or unsubstituted heterocyclic group, a substituted orunsubstituted alkylsulfonyl group, a substituted or unsubstitutedarylsulfonyl group, and anacyl group. Of these, a substituted orunsubstituted aryl group and a substituted or unsubstituted heterocyclicgroup are particularly preferred, a substituted or unsubstitutedheterocyclic group is especially preferred, and a substituted orunsubstituted, nitrogen-containing heterocyclic group is the mostpreferred. As examples of the substituent, there can be illustrated thesame ones that are illustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃,and W₄ in the foregoing general formula (2).

As preferred examples of Y and W₁ to W₄ in the general formula (2),there are independently illustrated a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, and a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthese, a hydrogen atom and a substituted or unsubstituted, straight orbranched alkyl group containing a total of from 1 to 8 carbon atoms arepreferred, a hydrogen atom and an alkyl group containing from 1 to 8carbon atoms are particularly preferred, and a hydrogen atom is the mostpreferred.

Preferred examples of R₁, R₂, P₁, P₂, Q₁, Q₂, and Win the generalformula (1) are described in detail below.

In the case where plural Ws exist, each of them independently representsa substituent. Each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independentlyrepresents a hydrogen atom or a substituent.

In the case where each of R₁, R₂, P₁, P₂, Q₁, Q₂, and W represents amonovalent substituent, examples of each of the monovalent substituentsindependently include a halogen atom, an alkyl group, a cycloalkylgroup, an aralkyl group, an alkenyl group, an alkynyl group, an arylgroup, a heterocyclic group, a cyano group, a hydroxyl group, a nitrogroup, an alkoxy group, an aryloxy group, a silyloxy group, aheterocyclic oxy group, an acyloxy group, a carbamoyloxy group, analkoxycarbonyloxy group, an aryloxycarbonyloxy group, an amino group (analkylamino group or an arylamino group), an acylamino group (an amidogroup), an aminocarbonylamino group (a ureido group), analkoxycarbonylamino group, an aryloxycarbonylamino group, asulfamoylamino group, an alkylsulfonylamino group, an arylsulfonylaminogroup, an alkylthio group, an arylthio group, a heterocyclic thio group,a sulfamoyl group, an alkylsulfinyl group, an arylsulfinyl group, analkylsulfonyl group, an arylsulfonyl group, an acyl group, anaryloxycarbonyl group, an alkoxycarbonyl group, a carbamoyl group, aphosphino group, a phosphinyl group, a phosphinyloxy group, aphosphinylamino group, a silyl group, an azo group, and an imido group,each of which may further have a substituent.

Particularly preferred examples of each of Ws are independently ahalogen atom, an alkyl group, an aryl group, a heterocyclic group, acyano group, a hydroxyl group, an alkoxy group, an amido group, a ureidogroup, an alkylsulfonylamino group, an arylsulfonylamino group, asulfamoyl group, an alkylsulfonyl group, an arylsulfonyl group, acarbamoyl group, and an alkoxycarbonyl group. Of these, a halogen atom,an alkyl group, an aryl group, a cyano group, a hydroxyl group, analkylsulfonyl group, an arylsulfonyl group, a heterocyclic group, and analkoxycarbonyl group are more preferred, and an alkyl group, an arylgroup, a hydroxyl group, and an alkoxycarbonyl group are the mostpreferred.

Particularly preferred examples of each of R₁, R₂, P₁, P₂, Q₁, and Q₂are independently a hydrogen atom, a halogen atom, an alkyl group, anaryl group, a heterocyclic group, a cyano group, a hydroxyl group, analkoxy group, an amido group, a ureido group, an alkylsulfonylaminogroup, an arylsulfonylamino group, a sulfamoyl group, an alkylsulfonylgroup, an arylsulfonyl group, a carbamoyl group, and an alkoxycarbonylgroup. Of these, a hydrogen atom, a halogen atom, an alkyl group, anaryl group, a cyano group, a hydroxyl group, an alkylsulfonyl group, anarylsulfonyl group, a heterocyclic group, and an alkoxycarbonyl groupare particularly preferred, and a hydrogen atom, an alkyl group, an arylgroup, a hydroxyl group, and an alkoxycarbonyl group are the mostpreferred.

R₁, R₂, P₁, P₂, Q₁, Q₂, and W will be described in more detail below.

The halogen atom represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W representsa chlorine atom, a bromine atom or an iodine atom. Of these, a halogenatom or a bromine atom is preferred, with a chlorine atom beingparticularly preferred.

The alkyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W includes asubstituted or unsubstituted alkyl group. The substituted orunsubstituted alkyl group is preferably an alkyl group containing from 1to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Among them, a hydroxyl group, an alkoxy group, a cyano group, a halogenatom, a sulfo group (optionally in the salt form thereof), and acarboxyl group (optionally in the salt form thereof) are preferred.Examples of the alkyl group include methyl, ethyl, n-propyl, i-propyl,n-butyl, i-butyl, s-butyl, t-butyl, n-octyl, eicosyl, 2-chloroethyl,hydroxyethyl, cyanoethyl, and 4-sulfobutyl.

The cycloalkyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Wincludes a substituted or unsubstituted cycloalkyl group. Thesubstituted or unsubstituted cycloalkyl group is preferably a cycloalkylgroup containing from 5 to 30 carbon atoms. As examples of thesubstituent, there can be illustrated the same substituents as have beenillustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in theforegoing general formula (2). Examples of the cycloalkyl group includecyclohexyl, cyclopentyl, and 4-n-dodecylcyclohexyl.

The aralkyl group represented by R₁, R₂, P₁, Q₂, Q₁, Q₂, and W includesa substituted or unsubstituted aralkyl group. The substituted orunsubstituted aralkyl group is preferably an aralkyl group containingfrom 7 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the aralkyl group include benzyl and 2-phenethyl.

The alkenyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W includesa straight, branched or cyclic, substituted or unsubstituted alkenylgroup. Preferably, there can be illustrated a substituted orunsubstituted alkenyl group containing from 2 to 30 carbon atoms, forexample, vinyl, allyl, prenyl, geranyl, oleyl, 2-cyclopenten-1-yl, and2-cyclohexen-1-yl.

The alkynyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W includesa substituted or unsubstituted alkynyl group containing from 2 to 30carbon atoms, for example, ethynyl and propargyl.

The aryl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W includes asubstituted or unsubstituted aryl group containing from 6 to 30 carbonatoms, for example, phenyl, p-tolyl, naphthyl, m-chlorophenyl, ando-hexadecanoylaminophenyl. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).

The heterocyclic group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W is amonovalent group formed by removing one hydrogen atom from a 5- or6-membered, substituted or unsubstituted, aromatic or non-aromaticheterocyclic compound, which may further be condensed with other ring.More preferably, the hetero ring is a 5- or 6-membered aromaticheterocyclic group containing from 3 to 30 carbon atoms. As examples ofthe substituent, there can be illustrated the same substituents as havebeen illustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in theforegoing general formula (2). To illustrate the heterocyclic groupwithout restricting the substitution position, there can be illustratedpyridyl, pyrazinyl, pyridazinyl, pyrimidinyl, triazinyl, quinolinyl,isoquinolinyl, quinazolinyl, cinnolinyl, phthalazinyl, quinoxalinyl,pyrrolyl, indolyl, furyl, benzofuryl, thienyl, benzothienyl, pyrazolyl,imidazolyl, benzimidazolyl, triazolyl, oxazolyl, benzoxazolyl,thiazolyl, benzothiazolyl, isothiazolyl, benzoisothiazolyl,thiadiazolyl, isoxazolyl, benzisoxazolyl, pyrrolidinyl, piperidyl,piperazinyl, imidazolyl, and thiazolyl.

Further, a pyridyl group, a pyrimidinyl group, a pyridazinyl group, anda triazinyl group are preferred. Of these, a pyridyl group, apyrimidinyl group, and a triazinyl group are preferred, and a 2-pyridylgroup, 2,4-pyrimidinyl group, and an s-trizinyl group are the mostpreferred.

The alkoxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W includes asubstituted or unsubstituted alkoxy group. The substituted orunsubstituted alkoxy group is preferably an alkoxy group containing from1 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the alkoxy group include methoxy, ethoxy, isopropoxy,n-octyloxy, methoxyethoxy, hydroxyethoxy, and 3-carboxypropoxy.

The aryloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted aryloxy group containing from6 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the aryloxy group include phenoxy, 2-methylphenoxy,4-t-butylphenoxy, 3-nitrophenoxy, and 2-tetradecanoylaminophenoxy.

The silyloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a silyloxy group containing from 3 to 20 carbon atoms, andexamples thereof include trimethylsilyloxy and t-butyldimethylsilyloxy.

The heterocyclic oxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Wis preferably a substituted or unsubstituted heterocyclic oxy groupcontaining from 2 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the heterocyclic oxy group include1-phenyltetrazol-5-oxy and 2-tetrahydropyranyloxy.

The acyloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a formyloxy group, a substituted or unsubstitutedalkylcarbonyloxy group containing from 2 to 30 carbon atoms, or asubstituted or unsubstituted arylcarbonyloxy group containing from 6 to30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the acyloxy group include formyloxy, acetyloxy, pivaloyloxy,stearoyloxy, benzoyloxy, and p-methoxyphenylcarbonyloxy.

The carbamoyloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted carbamoyloxy group containingfrom 1 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂ ^(, W) ₃, and W₄ in the foregoing general formula(2). Examples of the carbamoyloxy group includeN,N-dimethylcarbamoyloxy, N,N-diethylcarbamoyloxy,morpholinocarbonyloxy, N,N-di-n-octylaminocarbonyloxy, andN-n-octylcarbamoyloxy.

The alkoxycarbonyloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Wis preferably a substituted or unsubstituted alkoxycarbonyloxy groupcontaining from 2 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the alkoxycarbonyloxy group includemethoxycarbonyloxy, ethoxycarbonyloxy, t-butoxycarbonyloxy, andn-octylcarbonyloxy.

The aryloxycarbonyloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, andW is preferably a substituted or unsubstituted aryloxycarbonyloxy groupcontaining from 7 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the aryloxycarbonyloxy group includephenoxycarbonyloxy, p-methoxyphenoxycarbonyloxy, andp-n-hexadecyloxyphenoxycarbonyloxy.

The amino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted alkylamino group containingfrom 1 to 30 carbon atoms or a substituted or unsubstituted arylaminogroup containing from 6 to 30 carbon atoms. As examples of thesubstituent, there can be illustrated the same substituents as have beenillustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in theforegoing general formula (2). Examples of the amino group includeamino, methylamino, dimethylamino, aniline, N-methylanilino,diphenylamino, hydroxyethylamino, carboxyethylamino, sulfoethylamino,and 3,5-dicarboxyanilino.

The acylamino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a formylamino group, a substituted or unsubstitutedalkylcarbonylamino group containing from 1 to 30 carbon atoms, or asubstituted or unsubstituted arylcarbonylamino group containing from 6to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the acylamino group include formylamino, acetylamino,pivaloylamino, lauroylamino, benzoylamino, and3,4,5-tri-n-octyloxyphenylcarbonylamino.

The aminocarbonylamino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, andW is preferably a substituted or unsubstituted aminocarbonylamino groupcontaining from 1 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the aminocarbonylamino group includecarbamoylamino, N,N-dimethylaminocarbonylamino,N,N-diethylaminocarbonylamino, and morpholinocarbonylamino.

The alkoxycarbonylamino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, andW is preferably a substituted or unsubstituted alkoxycarbonylamino groupcontaining from 2 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the alkoxycarbonylamino group includemethoxycarbonylamino, ethoxycarbonylamino, t-butoxycarbonylamino,n-octadecyloxycarbonylamino, and N-methyl-methoxycarbonylamino.

The aryloxycarbonylamino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂,and W is preferably a substituted or unsubstituted ayloxycarbonylaminogroup containing from 7 to 30 carbon atoms. As examples of thesubstituent, there can be illustrated the same substituents as have beenillustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in theforegoing general formula (2). Examples of the aryloxycarbonylaminogroup include phenoxycarbonylamino, p-chlorophenoxycarbonylamino, andm-n-octylphenoxycarbonylamino.

The sulfamoylamino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted sulfamoylamino groupcontaining from 0 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the sulfamoylamino group includesulfamoylamino, N,N-dimethylaminosulfonylamino, andN-n-octylaminosulfonylamino.

The alkyl or arylsulfonylamino group represented by R₁, R₂, P₁, P₂, Q₁,Q₂, and W is preferably a substituted or unsubstitutedalkylsulfonylamino group containing from 1 to 30 carbon atoms or asubstituted or unsubstituted arylsulfonylamino group containing from 6to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the alkylsulfonylamino group and the arylsulfonylamino groupinclude methylsulfonylamino, butylsulfonylamino, phenylsulfonylamino,2,3,5-trichlorophenylsulfonylamino, and p-methylphenylsulfonylamino.

The alkylthio group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted alkylthio group containingfrom 1 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the alkylthio group include methylthio, ethylthio, andn-hexadecylthio.

The arylthio group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted arylthio group containing from6 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the arylthio group include phenylthio, p-chlorophenylthio,and m-methoxyphenylthio.

The heterocyclic thio group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Wis preferably a substituted or unsubstituted heterocyclic thio groupcontaining from 2 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the heterocyclic thio group include2-benzothiazolylthio and 1-phenyltetrazol-5-ylthio.

The sulfamoyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted sulfamoyl group containingfrom 0 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the sulfamoyl group include N-ethylsulfamoyl,N-(3-dodecyloxypropyl)sulfamoyl, N,N-dimethylsulfamoyl,N-acetylsulfamoyl, N-benzoylsulfamoyl, andN—(N′-phenylcarbamoyl)sulfamoyl).

The alkyl or arylsulfinyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂,and W is preferably a substituted or unsubstituted alkylsulfinyl groupcontaining from 1 to 30 carbon atoms or a substituted or unsubstitutedarylsulfinyl group containing from 6 to 30 carbon atoms. As examples ofthe substituent, there can be illustrated the same substituents as havebeen illustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in theforegoing general formula (2). Examples of the alkyl and arylsulfinylgroup include methylsulfinyl, ethylsulfinyl, phenylsulfinyl, andp-methylphenylsulfinyl.

The alkyl or arylsulfonyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂,and W is preferably a substituted or unsubstituted alkylsulfonyl groupcontaining from 1 to 30 carbon atoms or a substituted or unsubstitutedarylsulfonyl group containing from 6 to 30 carbon atoms. As examples ofthe substituent, there can be illustrated the same substituents as havebeen illustrated with respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in theforegoing general formula (2). Examples of the alkyl and arylsulfonylgroup include methylsulfonyl, ethylsulfonyl, phenylsulfonyl, andp-toluenesulfonyl.

The acyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a formyl group, a substituted or unsubstituted alkylcarbonylgroup containing from 2 to 30 carbon atoms, a substituted orunsubstituted arylcarbonyl group containing from 7 to 30 carbon atoms,or a heterocyclic carbonyl group containing from 4 to 30 carbon atomswherein the hetero ring binds to the carbonyl group through a carbonatom. As examples of the substituent, there can be illustrated the samesubstituents as have been illustrated with respect to X, Y, Z, W₀, W₁,W₂, W₃, and W₄ in the foregoing general formula (2). Examples of theacyl group include acetyl, pivaloyl, 2-chloroacetyl, stearoyl, benzoyl,p-n-octyloxyphenylcarbonyl, 2-pyridylcarbonyl, and 2-furylcarbonyl.

The aryloxycarbonyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Wis preferably a substituted or unsubstituted aryloxycarbonyl groupcontaining from 7 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the aryloxycarbonyl group includephenoxycarbonyl, o-chlorophenoxycarbonyl, m-nitrophenoxycarbonyl, andp-t-butylphenoxycarbonyl.

The alkoxycarbonyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted alkoxycarbonyl groupcontaining from 2 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W_(i), W₂, W₃, and W₄ in the foregoinggeneral formula (2). Examples of the alkoxycarbonyl group includemethoxycarbonyl, ethoxycarbonyl, and t-butoxycarbonyl,n-octadecyloxycarbonyl.

The carbamoyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted carbamoyl group containingfrom 1 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the carbamoyl group include carbamoyl, N-methylcarbamoyl,N,N-dimethylcarbamoyl, N,N-di-n-octylcarbamoyl, andN-(methylsulfonyl)carbamoyl.

The phosphino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted phosphino group containingfrom 2 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the phosphino group include dimethylphosphino,diphenylphosphino, and methylphenylphosphino.

The phosphinyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted phosphinyl group containingfrom 2 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the phosphinyl group include phosphinyl,dioctyloxyphosphinyl, and diethoxyphosphinyl.

The phosphinyloxy group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted phosphinyloxy group containingfrom 2 to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the phosphinyloxy group include diphenoxyphosphinyloxy anddioctyloxyphosphinyloxy.

The phosphinylamino group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Wis preferably a substituted or unsubstituted phosphinylamino groupcontaining from 2 to 30 carbon atoms. As examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2). Examples of the phosphinylamino group includedimethoxyphosphinylamino and dimethylaminophosphinylamino.

The silyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W ispreferably a substituted or unsubstituted silyl group containing from 3to 30 carbon atoms. As examples of the substituent, there can beillustrated the same substituents as have been illustrated with respectto X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2).Examples of the silyl group include trimethylsilyl,t-butyldimethylsilyl, and phenyldimethylsilyl.

Examples of the azo group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Winclude phenylazo, 4-methoxyphenylazo, 4-pivaloylaminophenylazo, and2-hydroxy-4-propanoylphenylazo.

Examples of the imido group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Winclude N-succinimido and N-phthalimido.

The heterocyclic thio group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Winclude a heterocyclic thio group having a substituent and anunsubstituted heterocyclic thio group. The heterocyclic thio grouppreferably has a 5- or 6-membered heterocyclic group. Examples of thesubstituent include ionic hydrophilic groups. Examples of theheterocyclic thio group include a 2-pyridylthio group.

The sulfinyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W includean alkylsulfinyl group and an arylsulfinyl group. Examples of thesulfinyl group include a 3-sulfopropylsulfinyl group and a3-carboxypropylsulfinyl group.

The phosphoryl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Winclude a phosphoryl group having a substituent and an unsubstitutedphosphoryl group. Examples of the phosphoryl group include aphenoxyphosphoryl group and a phenylphosphoryl group.

The acyl group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and W include anacyl group having a substituent and an unsubstituted acyl group. As theacyl group, an acyl group containing from 1 to 12 carbon atoms excludingthe substituent is preferred. Examples of the acyl group include anionic hydrophilic group. Examples of the acyl group include an acetylgroup and a benzoyl group.

The ionic hydrophilic group represented by R₁, R₂, P₁, P₂, Q₁, Q₂, and Winclude a sulfo group, a carboxyl group, a phosphono group, and aquaternary ammonium group. As the ionic hydrophilic group, a carboxylgroup and a sulfo group are preferred. The carboxyl group and the sulfogroup may be in the salts form thereof. Examples of the counter ionforming the salt include an ammonium ion, an alkali metal ion (forexample, calcium ion or barium ion), and an organic cation (for example,tetramethylguanidium ion).

In the case where each of R₁, R₂, P₁, P₂, Q₁, Q₂, and W represents adivalent group, the divalent group is preferably an alkylene group (forexample, methylene, ethylene, propylene, butylene or pentylene), analkenyl group (for example, ethenylene or propenylene), an alkynylenegroup (for example, ethynylene or propynylene), an arylene group (forexample, phenylene or naphthylene), a divalent heterocyclic group (forexample, a 6-chloro-1,3,5-triazine-2,4-diyl group, a pyrimidine-2,4-diylgroup, a pyrimidine-4,6-diyl group, a quinoxaline-2,3-diyl group, apyridazine-3,6-diyl group, —O—, —CO—, —NR′—(wherein R′ represents ahydrogen atom, an alkyl group or an aryl group), —S—, —SO₂—, —SO—, or acombination thereof (for example, —NHCH₂CH₂NH— or —NHCONH—).

The alkylene group, alkenylene group, alkynylene group, arylene group,divalent heterocyclic group, and the alkyl or aryl group of R′ may havea substituent.

As examples of the substituent, there can be illustrated the samesubstituents as have been illustrated with respect to X, Y, Z, W₀, W₁,W₂, W₃, and W₄ in the foregoing general formula (2).

The alkyl group and the aryl group of R′ described above are the same asthe substituent examples having been illustrated with respect to thecase where each of R₁, R₂, P₁, P₂, Q₁, Q₂, and W represents an alkylgroup or an aryl group.

More preferably, the divalent group is an alkylene group containing 10or less carbon atoms, an alkenylene group containing 10 or less carbonatoms, an alkynylene group containing 10 or less carbon atoms, anarylene group containing from 6 to 10 carbon atoms, a divalentheterocyclic group, —S—, —SO—, —SO₂— or a combination thereof (forexample, —SCH₂CH₂S— or —SCH₂CH₂CH₂S—).

The divalent linking group contains a total of preferably from 0 to 50carbon atoms, more preferably from 0 to 30 carbon atoms, most preferablyfrom 0 to 10 carbon atoms.

In the case where each of R₁, R₂, P₁, P₂, Q₁, Q₂, and W represents atrivalent group, the trivalent group is preferably a trivalenthydrocarbon group, a trivalent heterocyclic group, >N— or a combinationthereof with a divalent group (for example, >NCH₂CH₂NH— or >NCONH—).

The trivalent linking group contains a total of preferably from 0 to 50carbon atoms, more preferably from 0 to 30 carbon atoms, most preferablyfrom 0 to 10 carbon atoms.

In the general formula (1), t represents an integer of from 0 to 4,preferably from 0 to 2, more preferably 1 or 2, most preferably 1.

Preferred examples of the 5- to 6-membered heterocyclic groupconstituted by G in the general formula (1) are 5- or 6-membered,substituted or unsubstituted, aromatic or non-aromatic heterocyclicgroups, which may be further condensed with other ring. More preferredare 5- or 6-membered aromatic heterocyclic groups containing from 3 to30 carbon atoms.

To illustrate the heterocyclic group represented by G withoutrestricting substitution positions, there can be illustrated pyridine,pyrazine, pyridazine, pyrimidine, triazine, quinoline, isoquinoline,quinazoline, cinnoline, phthalazine, quinoxaline, pyrrole, indole,furan, benzofuran, thiophene, benzothiophene, pyrazole, imidazole,benzimidazole, triazole, oxazole, benzoxazole, thiazole, benzothiazole,isothiazole, benzoisothiazole, thiadiazole, isoxazole, benzisoxazole,pyrrolidine, piperidine, piperazine, imidazolidine, thiazoline, andsulfolane.

More preferred are a pyridine ring, a pyrazine ring, a pyridazine ring,a pyrimidine ring, and a triazine ring. Of them, an s-triazine ring, apyrimidine ring, a pyridazine ring, and a pyrazine ring are preferred,with a 2,3-pyridazine ring, a 2,4-pyrimidine ring, a 2,5-pyrazine ring,a 2,6-pyrimidine ring, and an s-triazine ring being most preferred.

In the case where the heterocyclic group constituted by G is a groupwhich can further have a substituent, as examples of the substituent,there can be illustrated the same substituents as have been illustratedwith respect to X, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing generalformula (2).

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formula (1), thosecompounds are preferred wherein at least one of the various substituentsis the preferred group having been described hereinbefore, thosecompounds are more preferred wherein more of the various substituentsare the preferred groups having been described hereinbefore, and thosecompounds are most preferred wherein all of the substituents are thepreferred groups having been described hereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formula (1) contain thefollowing (a) to (k).

(a) G is preferably a 5- or 6-membered, nitrogen-containing heterocyclicgroup and, to illustrate without restricting the substitution positions,an s-triazine ring, a pyrimidine ring, a pyridazine ring, a pyrazinering, a pyridine ring, an imidazole ring, a pyrazole ring, and a pyrrolering are preferred. Of these, an s-triazine ring, a pyrimidine ring, apyridazine ring, and a pyrazine ring are preferred, with a2,3-pyridazine ring, a 2,4-pyrimidine ring, a 2,5-pyrazine ring, a2,6-pyrimidine ring, and an s-triazine ring being most preferred.(b) W is preferably a hydroxyl group, a cyano group, a substituted orunsubstituted carbamoyl group, a substituted or unsubstituted aminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted alkylthiogroup, or a substituted or unsubstituted arylthio group, and a hydroxylgroup, a substituted or unsubstituted amino group, a substituted orunsubstituted alkoxy group, and a substituted or unsubstituted alkylthiogroup are particularly preferred, with a hydroxyl group and an aminogroup being most preferred.(c) t represents an integer of from 0 to 4, preferably from 0 to 2, morepreferably 1 or 2, most preferably 1.(d) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are preferred, with a methyl group and a t-butyl group being mostpreferred.(e) Preferably, each of P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted acyl group, a substituted or unsubstitutedalkylsulfonyl group, or a substituted or unsubstituted arylsulfonylgroup. Particularly preferred are a hydrogen atom, a substituted orunsubstituted alkyl group, and a substituted or unsubstituted acylgroup. Of them, a hydrogen atom is particularly preferred.(f) Preferably, each of Het-1 and Het-2 is independently selected fromthe aromatic heterocyclic groups (1) to (15) represented by theforegoing general formula (2). Of them, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are particularly preferred, (2), (5), (6), (7), and (10)are more preferred, and (2) and (7) are still more preferred, with (2)being most preferred.(g) Particularly preferred examples of X are a cyano group, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, and a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(h) Y is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group containing a total of from 1 to 12 carbon atoms, asubstituted or unsubstituted aryl group containing a total of from 6 to18 carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, and a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are particularly preferred, with ahydrogen atom being most preferred.(i) Z is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group. Of them, a substituted orunsubstituted aryl group and a substituted or unsubstituted heterocyclicgroup are preferred, a substituted or unsubstituted heterocyclic groupis preferred, and a substituted or unsubstituted, nitrogen-containingheterocyclic group is most preferred.(j) W₀ is particularly preferably a cyano group, an alkylsulfonyl groupcontaining from 1 to 12 carbon atoms, an arylsulfonyl group containingfrom 6 to 18 carbon atoms, or a sulfamoyl group containing from 0 to 12carbon atoms. Of them, a cyano group, a methanesulfonyl group, and aphenylsulfonyl group are preferred, with a cyano group being mostpreferred.(k) Each of W₁ to W₄ is preferably a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing from 6 to 18carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are more preferred, and a hydrogenatom is most preferred.

The azo pigments represented by the foregoing general formula (1) arepreferably those azo pigments which are represented by the followinggeneral formula (3).

Azo pigments represented by the general formula (3), the tautomersthereof, and the salts or hydrates thereof will be described below.

Of the azo pigments represented by the foregoing general formula (1),those azo pigments which are represented by the following generalformula (3) are preferred.

Azo pigments represented by the general formula (3), the tautomersthereof, and the salts or hydrates thereof will be described below.

In the general formula (3), each of R₁, R₂, G, W, t, Het-1, and Het-2 isindependently the same as R₁, R₂, G, W, t, Het-1, and Het-2 in thegeneral formula (3). The asterisk * shows the point of attachment to theazo linkage in the general formula (3).

R₁, R₂, G, W, t, Het-1, and Het-2 will be described in more detailbelow.

Examples of each of the substituents R₁ and R₂ are independently thesame as those of each of R₁ and R₂ in the foregoing general formula (1),and preferred examples thereof are also the same as described there.

Examples of G are the same as those of G in the foregoing generalformula (1), and preferred examples thereof are also the same asdescribed there.

Examples of the substituent W are the same as those of W in theforegoing general formula (1), and preferred examples thereof are alsothe same as described there.

Examples of t is the same as those of t in the foregoing general formula(1), and preferred examples thereof are also the same as describedthere.

Examples of each of the heterocyclic groups represented by Het-1 andHet-2 are independently the same as those of each of Het-1 and Het-2 inthe foregoing general formula (1), and preferred examples thereof arealso the same as described there.

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formula (3), thosecompounds are preferred wherein at least one of the various substituentsis the preferred group having been described hereinbefore, thosecompounds are more preferred wherein more of the various substituentsare the preferred groups having been described hereinbefore, and thosecompounds are most preferred wherein all of the substituents are thepreferred groups having been described hereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formula (3) contain thefollowing (a) to (j).

(a) G is preferably a 5- or 6-membered, nitrogen-containing heterocyclicgroup and, to illustrate without restricting the substitution positions,an s-triazine ring, a pyrimidine ring, a pyridazine ring, a pyrazinering, a pyridine ring, an imidazole ring, a pyrazole ring, and a pyrrolering are preferred. Of these, an s-triazine ring, a pyrimidine ring, apyridazine ring, and a pyrazine ring are preferred, with a2,3-pyridazine ring, a 2,4-pyrimidine ring, a 2,5-pyrazine ring, a2,6-pyrimidine ring, and an s-triazine ring being most preferred.(b) W is preferably a hydroxyl group, a cyano group, a substituted orunsubstituted carbamoyl group, a substituted or unsubstituted aminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted alkylthiogroup, or a substituted or unsubstituted arylthio group, and a hydroxylgroup, a substituted or unsubstituted amino group, a substituted orunsubstituted alkoxy group, and a substituted or unsubstituted alkylthiogroup are particularly preferred, with a hydrogen atom, a hydroxylgroup, and an amino group being most preferred.(c) t represents an integer of from 0 to 4, preferably from 0 to 2, morepreferably 1 or 2, most preferably 1.(d) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are preferred, with a methyl group and a t-butyl group being mostpreferred.(e) Preferably, each of Het-1 and Het-2 is independently selected fromthe aromatic heterocyclic groups (1) to (15) represented by theforegoing general formula (2). Of them, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are particularly preferred, (2), (5), (6), (7), and (10)are more preferred, and (2) and (7) are still more preferred, with (2)being most preferred.(f) Particularly preferred examples of X are a cyano group, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, and a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(g) Y is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group containing a total of from 1 to 12 carbon atoms, asubstituted or unsubstituted aryl group containing a total of from 6 to18 carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, and a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are particularly preferred, with ahydrogen atom being most preferred.(h) Z is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group. Of them, a substituted orunsubstituted aryl group and a substituted or unsubstituted heterocyclicgroup are preferred, a substituted or unsubstituted heterocyclic groupis preferred, and a substituted or unsubstituted, nitrogen-containingheterocyclic group is most preferred.(i) W₀ is particularly preferably a cyano group, an alkylsulfonyl groupcontaining from 1 to 12 carbon atoms, an arylsulfonyl group containingfrom 6 to 18 carbon atoms, or a sulfamoyl group containing from 0 to 12carbon atoms. Of them, a cyano group, a methanesulfonyl group, and aphenylsulfonyl group are preferred, with a cyano group being mostpreferred.(j) Each of W₁ to W₄ is preferably a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing from 6 to 18carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are more preferred, and a hydrogenatom is most preferred.

Of the azo pigments represented by the foregoing general formulae (1)and (3), those azo pigments which are represented by the followinggeneral formula (4) are preferred.

The azo pigments represented by the following general formula (4), thetautomers thereof, and the salts or hydrates thereof will be describedin detail below.

Examples of each of the substituents R₁, R₂, G, W, and t areindependently the same as those of each of R₁, R₂, G, W, and t in theforegoing general formula (3). Each of X₁ and X₂ independentlyrepresents an electron-withdrawing group having a Hammett's σp value of0.2 or more. Each of Y₁, Y₂, Z_(i), and Z₂ independently represents ahydrogen atom or a substituent.

R₁, R₂, G, W, t, Y₁, Y₂, Z_(i), and Z₂ will be described in more detailbelow.

Examples of each of the substituents R₁ and R₂ are independently thesame as those of each of R₁ and R₂ in the foregoing general formula (3),and preferred examples thereof are also the same as described there.

Examples of G are the same as those of G in the foregoing generalformula (3), and preferred examples thereof are also the same asdescribed there.

Examples of the substituent W are the same as those of W in theforegoing general formula (3), and preferred examples thereof are alsothe same as described there.

Examples of t is the same as those of t in the foregoing general formula(3), and preferred examples thereof are also the same as describedthere.

Examples of each of the substituents of X₁ and X₂ are independently thesame as those of X in the foregoing general formula (2).

Examples of each of the substituents of Y₁ and Y₂ are independently thesame as those of Yin the foregoing general formula (2).

Examples of each of the substituents of Z₁ and Z₂ are independently thesame as those of Z in the foregoing general formula (2).

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formula (4), thosecompounds are preferred wherein at least one of the various substituentsis the preferred group having been described hereinbefore, thosecompounds are more preferred wherein more of the various substituentsare the preferred groups having been described hereinbefore, and thosecompounds are most preferred wherein all of the substituents are thepreferred groups having been described hereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formula (4) contain thefollowing (a) to (g).

(a) G is preferably a 5- or 6-membered, nitrogen-containing heterocyclicgroup and, to illustrate without restricting the substitution positions,an s-triazine ring, a pyrimidine ring, a pyridazine ring, a pyrazinering, a pyridine ring, an imidazole ring, a pyrazole ring, and a pyrrolering are preferred. Of these, an s-triazine ring, a pyrimidine ring, apyridazine ring, and a pyrazine ring are preferred, with a2,3-pyridazine ring, a 2,4-pyrimidine ring, a 2,5-pyrazine ring, a2,6-pyrimidine ring, and an s-triazine ring being most preferred.(b) W is preferably a hydroxyl group, a cyano group, a substituted orunsubstituted carbamoyl group, a substituted or unsubstituted aminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted alkylthiogroup, or a substituted or unsubstituted arylthio group, and a hydroxylgroup, a substituted or unsubstituted amino group, a substituted orunsubstituted alkoxy group, and a substituted or unsubstituted alkylthiogroup are particularly preferred, with a hydroxyl group and an aminogroup being most preferred.(c) t represents an integer of from 0 to 4, preferably from 0 to 2, morepreferably 1 or 2, most preferably 1.(d) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are preferred, with a methyl group and a t-butyl group being mostpreferred.(e) Particularly preferably, each of X₁ and X₂ is independently a cyanogroup, an alkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, or a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(f) Particularly preferably, each of Y₁ and Y₂ is independently ahydrogen atom, a substituted or unsubstituted alkyl group containing atotal of from 1 to 12 carbon atoms, a substituted or unsubstituted arylgroup containing a total of from 6 to 18 carbon atoms, or a substitutedor unsubstituted heterocyclic group containing a total of from 4 to 12carbon atoms. Of them, a hydrogen atom and a straight or branched alkylgroup containing a total of from 1 to 8 carbon atoms are preferred, anda hydrogen atom and an alkyl group containing from 1 to 8 carbon atomsare particularly preferred, with a hydrogen atom being most preferred.(g) Particularly preferably, each of Z₁ and Z₂ is independently ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted cycloalkyl group, a substituted or unsubstitutedalkenyl group, a substituted or unsubstituted alkynyl group, asubstituted or unsubstituted aralkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted heterocyclicgroup. Of them, a substituted or unsubstituted aryl group and asubstituted or unsubstituted heterocyclic group are preferred, asubstituted or unsubstituted heterocyclic group is more preferred, and asubstituted or unsubstituted, nitrogen-containing heterocyclic group ismost preferred.

Of the azo pigments represented by the foregoing general formulae (1)and (3), those azo pigments which are represented by the followinggeneral formula (5) are preferred.

The azo pigments represented by the following general formula (5), thetautomers thereof, and the salts or hydrates thereof will be describedin detail below.

In the general formula (5), each of R₁, R₂, Het-1, and Het-2 isindependently the same as R₁, R₂, Het-1, and Het-2 in the generalformula (3). The asterisk * shows the point of attachment to the azolinkage in the general formula (5).

R₁, R₂, W, Het-1, and Het-2 will be described in more detail below.

Examples of each of the substituents R₁ and R₂ are independently thesame as those of each of R₁ and R₂ in the foregoing general formula (3),and preferred examples thereof are also the same as described there.

Examples of the substituent W are the same as those of W in theforegoing general formula (3), and preferred examples thereof are alsothe same as described there.

Examples of each of the heterocyclic groups represented by Het-1 andHet-2 are independently the same as those of each of Het-1 and Het-2 inthe foregoing general formula (3), and preferred examples thereof arealso the same as described there.

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formula (5), thosecompounds are preferred wherein at least one of the various substituentsis the preferred group having been described hereinbefore, thosecompounds are more preferred wherein more of the various substituentsare the preferred groups having been described hereinbefore, and thosecompounds are most preferred wherein all of the substituents are thepreferred groups having been described hereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formula (5) contain thefollowing (a) to (i).

(a) W is preferably a hydroxyl group, a substituted or unsubstitutedamino group, a substituted or unsubstituted alkoxy group, a substitutedor unsubstituted aryloxy group, a substituted or unsubstituted alkylthiogroup, or a substituted or unsubstituted arylthio group, and a hydroxylgroup, a substituted or unsubstituted amino group, a substituted orunsubstituted alkoxy group, and a substituted or unsubstituted alkylthiogroup are particularly preferred, with a hydroxyl group and an aminogroup being most preferred.(b) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are preferred, with a methyl group and a t-butyl group being mostpreferred.(c) Preferably, each of Het-1 and Het-2 is independently selected fromthe aromatic heterocyclic groups (1) to (15) represented by theforegoing general formula (2). Of them, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are particularly preferred, (2), (5), (6), (7), and (10)are more preferred, and (2) and (7) are still more preferred, with (2)being most preferred.(d) Particularly preferred examples of X are a cyano group, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, and a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(e) Y is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group containing a total of from 1 to 12 carbon atoms, asubstituted or unsubstituted aryl group containing a total of from 6 to18 carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, and a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are particularly preferred, with ahydrogen atom being most preferred.Z is preferably a hydrogen atom, a substituted or unsubstituted alkylgroup, a substituted or unsubstituted cycloalkyl group, a substituted orunsubstituted alkenyl group, a substituted or unsubstituted alkynylgroup, a substituted or unsubstituted aralkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted heterocyclicgroup. Of them, a substituted or unsubstituted aryl group and asubstituted or unsubstituted heterocyclic group are preferred, asubstituted or unsubstituted heterocyclic group is particularlypreferred, and a substituted or unsubstituted, nitrogen-containingheterocyclic group is most preferred.(g) W₀ is particularly preferably a cyano group, an alkylsulfonyl groupcontaining from 1 to 12 carbon atoms, an arylsulfonyl group containingfrom 6 to 18 carbon atoms, or a sulfamoyl group containing from 0 to 12carbon atoms. Of them, a cyano group, a methanesulfonyl group, and aphenylsulfonyl group are preferred, with a cyano group being mostpreferred.(h) Each of W₁ to W₄ is preferably a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing from 6 to 18carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are more preferred, and a hydrogenatom is most preferred.(i) As to pigment mother nucleus, those azo pigments are preferredwherein the main component of mother nucleus is an azo pigment mothernucleus among an azo pigment nucleus and a hydrazone pigment nucleus. Ofthem, those pigments are most preferred which have the azo pigmentmother nucleus and are of a single crystal form.

Of the azo pigments represented by the foregoing general formula (5),those azo pigments which are represented by the following generalformula (6) are preferred.

The azo pigments represented by the following general formula (6), thetautomers thereof, and the salts or hydrates thereof will be describedin detail below.

In the general formula (6), each of R₁ and R₂ independently represents ahydrogen atom or a monovalent substituent, and each of Het-1 and Het-2is independently the same as Het-1 and Het-2 in the above generalformula (5). The asterisk * shows the point of attachment to the azolinkage in the general formula (6).

R₁, R₂, Het-1, and Het-2 will be described in more detail below.

Examples of each of the substituents R₁ and R₂ are independently thesame as those of each of R₁ and R₂ in the above general formula (6), andpreferred examples thereof are also the same as described there.

Examples of each of the heterocyclic groups represented by Het-I andHet-2 are independently the same as those of each of Het-1 and Het-2 inthe above general formula (6), and preferred examples thereof are alsothe same as described there.

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formula (6), thosecompounds are preferred wherein at least one of the various substituentsis the preferred group having been described hereinbefore, thosecompounds are more preferred wherein more of the various substituentsare the preferred groups having been described hereinbefore, and thosecompounds are most preferred wherein all of the substituents are thepreferred groups having been described hereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formula (6) contain thefollowing (a) to (g).

(a) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are more preferred, with a methyl group and a t-butyl group beingmost preferred.(b) Preferably, each of Het-1 and Het-2 is independently selected fromthe aromatic heterocyclic groups (1) to (15) represented by theforegoing general formula (2). Of them, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are particularly preferred, (2), (5), (6), (7), and (10)are more preferred, and (2) and (7) are still more preferred, with (2)being most preferred.(c) Particularly preferred examples of X are a cyano group, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, and a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(d) Y is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group containing a total of from 1 to 12 carbon atoms, asubstituted or unsubstituted aryl group containing a total of from 6 to18 carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, and a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are particularly preferred, with ahydrogen atom being most preferred.(e) Z is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group. Of them, a substituted orunsubstituted aryl group and a substituted or unsubstituted heterocyclicgroup are preferred, a substituted or unsubstituted heterocyclic groupis particularly preferred, and a substituted or unsubstituted,nitrogen-containing heterocyclic group is most preferred.(f) W₀ is particularly preferably a cyano group, an alkylsulfonyl groupcontaining from 1 to 12 carbon atoms, an arylsulfonyl group containingfrom 6 to 18 carbon atoms, or a sulfamoyl group containing from 0 to 12carbon atoms. Of them, a cyano group, a methanesulfonyl group, and aphenylsulfonyl group are preferred, with a cyano group being mostpreferred.(g) Each of W₁ to W₄ is preferably a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing from 6 to 18carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are more preferred, and a hydrogenatom is most preferred.

The invention also includes in its scope tautomers of the azo pigmentsrepresented by the general formulae (1), (3), (4), and (6). Although thegeneral formulae (1), (3), (4), and (6) are shown in the form of limitedstructure among several tautomer forms which are possible in view ofchemical structure, the azo pigments may be tautomers of other structurethan the shown one, and may be used as a mixture containing pluraltautomers. For example, with the pigment represented by the generalformula (6), azo-hydrazone tautomers represented by the followinggeneral formulae (6′) to (6′″) can be considered.

The general formulae (6′) to (6′″) will be described in detail below.

In the general formulae (6′) to (6″), each of R₁ and R₂ independentlyrepresents a hydrogen atom or a monovalent substituent, each of Het-1and Het-2 independently is independently the same as Het-1 and Het-2 inthe foregoing general formula (5), and the asterisk * shows the point ofattachment to the azo linkage in the general formula (6).

R₁, R₂, Het-1, and Het-2 will be described in more detail below.

Examples of each of the substituents R₁ and R₂ are independently thesame as those of each of R₁ and R₂ in the above general formula (5), andpreferred examples thereof are also the same as described there.

Examples of each of the heterocyclic groups represented by Het-1 andHet-2 are independently the same as those of each of Het-1 and Het-2 inthe above general formula (5), and preferred examples thereof are alsothe same as described there.

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formulae (6′) to(6″), those compounds are preferred wherein at least one of the varioussubstituents is the preferred group having been described hereinbefore,those compounds are more preferred wherein more of the varioussubstituents are the preferred groups having been describedhereinbefore, and those compounds are most preferred wherein all of thesubstituents are the preferred groups having been describedhereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formulae (6′) to (6′″) containthe following (a) to (g).

(a) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are more preferred, with a methyl group and a t-butyl group beingmost preferred.(b) Preferably, each of Het-1 and Het-2 is independently selected fromthe aromatic heterocyclic groups (1) to (15) represented by theforegoing general formula (2). Of them, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are particularly preferred, (2), (5), (6), (7), and (10)are more preferred, and (2) and (7) are still more preferred, with (2)being most preferred.(c) Particularly preferred examples of X are a cyano group, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, and a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(d) Y is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group containing a total of from 1 to 12 carbon atoms, asubstituted or unsubstituted aryl group containing a total of from 6 to18 carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, and a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are particularly preferred, with ahydrogen atom being most preferred.(e) Z is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group. Of them, a substituted orunsubstituted aryl group and a substituted or unsubstituted heterocyclicgroup are preferred, a substituted or unsubstituted heterocyclic groupis particularly preferred, and a substituted or unsubstituted,nitrogen-containing heterocyclic group is most preferred.(f) W₀ is particularly preferably a cyano group, an alkylsulfonyl groupcontaining from 1 to 12 carbon atoms, an arylsulfonyl group containingfrom 6 to 18 carbon atoms, or a sulfamoyl group containing from 0 to 12carbon atoms. Of them, a cyano group, a methanesulfonyl group, and aphenylsulfonyl group are preferred, with a cyano group being mostpreferred.(g) Each of W₁ to W₄ is preferably a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing from 6 to 18carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are more preferred, and a hydrogenatom is most preferred.The azo pigment of the general formula (6) may be used as a mixturecontaining, for example, the tautomers thereof represented by thegeneral formula (6′) to (6′″). It is preferred, however, that the azopigment represented by the general formula (6) constitutes a majorcomponent.

Of the azo pigments represented by the foregoing general formula (4),those azo pigments which are represented by the following generalformula (7) are preferred.

The azo pigments represented by the following general formula (7), thetautomers thereof, and the salts or hydrates thereof will be describedin detail below.

In the general formula (7), each of R₁, R₂, X₁, X₂, Y₁, and Y₂ isindependently the same as R₁, R₂, X₁, X₂, Y₁, and Y₂ in the generalformula (4), G₁ represents the non-metallic atoms necessary to completea 5- to 6-membered heterocyclic group, W represents a substituentcapable of binding to to the heterocyclic group constituted by G₁, trepresents an integer of from 0 to 4, each of G₁₁ and G₁₂ independentlyrepresents the non-metallic atoms necessary to complete a 5- to6-membered heterocyclic group, each of the heterocyclic groupsconstituted by G₁₁ and G₁₂ may independently be unsubstituted or mayhave a substituent, and each of the heterocyclic groups may be amonocyclic ring or may have a condensed ring.

R₁, R₂, G₁, W, t, X₁, X₂, Y₁, Y₂, G₁₁, and G₁₂ will be described in moredetail below.

Examples of each of the substituents R₁ and R₂ are independently thesame as those of each of R₁ and R₂ in the foregoing general formula (4).

Examples of G₁ are the same as those of G in the foregoing generalformula (4), and preferred examples thereof as also the same asdescribed there.

Examples of the substituent W are the same as those of W in theforegoing general formula (4), and preferred examples thereof are alsothe same as described there.

Examples of t is the same as those of t in the foregoing general formula(4), and preferred examples thereof are also the same as describedthere.

Examples of each of the substituents of X_(i) and X₂ are independentlythe same as those of X₁ and X₂ in the foregoing general formula (4), andpreferred examples thereof are also the same as described there.

Examples of each of the substituents of Y₁ and Y₂ are independently thesame as those of Y₁ and Y₂ in the foregoing general formula (4), andpreferred examples thereof are also the same as described there.

At least one of the nitrogen-containing heterocyclic groups respectivelyrepresented by G₁₁ and G₁₂ is preferably represented by any one of (G-1)to (G-13) in the following general formula (8).

In the above general formula (8), * in (G-1) to (G-13) shows the pointof attachment to the N atom on the pyrazole ring represented in theabove general formula (7), each of Z₁₁ to Z₁₄ represents a substituentcapable of binding to the heterocyclic group, and G′ in (G-13)represents the non-metallic atoms necessaty to complete a heterocyclicgroup.

Each of Z₁₁, Z₁₂, Z₁₃, and Z₁₄ in (G-1) to (G-13) in the general formula(8) is a hydrogen atom or is the same as the substituent represented byX, Y, Z, W₀, W₁, W₂, W₃, and W₄ in the foregoing general formula (2),and preferred examples thereof are also the same as described there.

Examples of the heterocyclic group represented by G′ in (G-13) in thegeneral formula (8) are the same as the preferred examples of the 5- to6-membered heterocyclic group constituted by G₁ in the general formula(7) as long as they can form a condensed ring, and preferred examplesthereof are also the same as described there.

With respect to a preferred combination of the substituents in thepigment of the invention represented by the general formula (7), thosecompounds are preferred wherein at least one of the various substituentsis the preferred group having been described hereinbefore, thosecompounds are more preferred wherein more of the various substituentsare the preferred groups having been described hereinbefore, and thosecompounds are most preferred wherein all of the substituents are thepreferred groups having been described hereinbefore.

Particularly preferred combinations of the groups in the azo pigments ofthe invention represented by the general formula (7) contain thefollowing (a) to (g).

(a) G₁₁ is preferably a 5- or 6-membered, nitrogen-containingheterocyclic group and, to illustrate without restricting thesubstitution positions, an s-triazinyl group, a pyrimidinyl group, apyridazinyl group, a pyrazyl group, a pyridyl group, an imidazolylgroup, a pyrazolyl group, and a pyrrolyl group are preferred. Of these,an s-triazinyl group, a pyrimidinyl group, a pyridazinyl group, and apyrazinyl group are preferred, with a 2,3-pyridazyl group, a2,4-pyrimidinyl group, a 2,5-pyrazyl group, a 2,6-pyrimidinyl group, andan s-triazinyl group being most preferred.(b) W is preferably a hydroxyl group, a cyano group, a substituted orunsubstituted carbamoyl group, a substituted or unsubstituted aminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted alkylthiogroup, or a substituted or unsubstituted arylthio group, and a hydroxylgroup, a substituted or unsubstituted amino group, a substituted orunsubstituted alkoxy group, and a substituted or unsubstituted alkylthiogroup are particularly preferred, with a hydroxyl group and an aminogroup being most preferred.(c) t represents an integer of from 0 to 4, preferably from 0 to 2, morepreferably 1 or 2, most preferably 1.(d) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are more preferred, with a methyl group and a t-butyl group beingmost preferred.(e) Particularly preferably, each of X₁ and X₂ is independently a cyanogroup, an alkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, or a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(f) Particularly preferably, each of Y₁ and Y₂ is independently ahydrogen atom, a substituted or unsubstituted alkyl group containing atotal of from 1 to 12 carbon atoms, a substituted or unsubstituted arylgroup containing a total of from 6 to 18 carbon atoms, or a substitutedor unsubstituted heterocyclic group containing a total of from 4 to 12carbon atoms. Of them, a hydrogen atom and a straight or branched alkylgroup containing a total of from 1 to 8 carbon atoms are preferred, anda hydrogen atom and an alkyl group containing from 1 to 8 carbon atomsare particularly preferred, with a hydrogen atom being most preferred.(g) Particularly preferably, each of G₁₁ and G₁₂ is independently (G-1),(G-2), (G-3), (G-4), (G-5), (G-6), (G-7), (G-9), (G-10), and (G-11) inthe general formula (8). Of them, (G-1), (G-2), (G-3), (G-4), (G-5), and(G-6) are particularly preferred, (G-1), (G-3), (G-4), (G-5), and (G-6)are more preferred, and (G-1), (G-4), and (G-6) are most preferred.

With the azo pigments represented by the foregoing general formulae (1),(3), (4), (5), (6), and (7), azo-hydrazone tautomers thereof can beconsidered.

Also, in the invention, the azo pigments represented by the generalformula (1) preferably have a substituent forming an intramolecularhydrogen bond or an intramolecular cross-linked hydrogen bond. It ispreferable to have a substitutent forming one or more intramolecularhydrogen bonds, more preferable to have a substituent forming two ormore intramolecular hydrogen bonds, still more preferable to have asubstituent forming one or more intramolecular hydrogen bonds and one ormore intramolecular cross-linked hydrogen bonds, and especiallypreferable to have a substituent forming two or more intramolecularhydrogen bonds and one or more intramolecular cross-linked hydrogenbonds.

Of the azo pigments represented by the foregoing general formulae (1),(3), (4), (5), (6), and (7), azo pigments represented by the followinggeneral formulae (7-1), (7-2) and (7-3) can be illustrated as examplesof particularly preferred azo pigments.

As a reason why this structure is preferred, there can be illustratedthe fact that, as is shown by the general formula (7-1), the nitrogenatoms constituting the hetero rings contained in the azo pigmentstructure, hydrogen atoms of the amino group, and hetero atoms (nitrogenatom of the azo group or its tautomer of hydrazone group and oxygen atomof the carbonyl group or a nitrogen atom of the amino group) tend toeasily form at least one or more intramolecular hydrogen bond.

More preferably, as is shown by the following general formula (7-2), thenitrogen atoms constituting the hetero rings contained in the azopigment structure, hydrogen atoms of the amino group, and hetero atoms(nitrogen atom of the azo group or its tautomer of hydrazone group andoxygen atom of the carbonyl group or a nitrogen atom of the amino group)tend to easily form at least two or more intramolecular hydrogen bonds.

Particularly preferably, as is shown by the following general formula(7-3), the nitrogen atoms constituting the hetero rings contained in theazo pigment structure, hydrogen atoms of the amino group, and heteroatoms (nitrogen atom of the azo group or its tautomer of hydrazone groupand oxygen atom of the carbonyl group or a nitrogen atom of the aminogroup) tend to easily form at least two or more intramolecular hydrogenbond and, in addition, tend to easily form at least one or moreintramolecular cross-linked hydrogen bonds.

As a result, flatness of the molecule is enhanced, the intramolecularand intermolecular mutual action is improved, crystallinity of the azopigment represented by the general formula (7-1), further the generalformula (7-2) and, particularly, the general formula (7-3) is enhanced(higher structure of the pigment becoming liable to be easily formed),and hence performances required as pigments, i.e., light fastness, heatstability, moist heat stability, water resistance, gas resistance,and/or solvent resistance, can markedly be improved, thus such pigmentsbeing most preferred examples.

In the general formulae (7-1) to (7-3), R₁, R₂ G₁, Het-1 and Het-2 arerespectively the same as R₁, R₂ G₁, Het-1 and Het-2 in the above generalformula (1), and G₁₁, G₁₂, X₁, X₂, Y₁ and Y₂ are respectively the sameas G₁₁, G₁₂, X₁, X₂, Y₁ and Y₂ in the general formula (7).

In view of dispersibility of pigments, with the azo pigments representedby the foregoing general formulae (1), (3), (4), (5), (6), and (7), apeak absorption intensity in the range of from 1700 to 1730 cm⁻¹ in theIR absorption spectrum is preferably 1/3 or less of a peak absorptionintensity in the range of from 1620 to 1670 cm⁻¹. More preferably, λmaxexists between 400 and 480 nm, and, most preferably, the above-mentionedabsorption intensity ratio is 1/5 or less.

Specific examples of the azo pigments (illustrative azo pigments Pig-1to Pig-80) represented by the general formulae (1), (3), (4), (5), (6),and (7) will be shown below which, however, do not limit azo pigments tobe used in the invention.

Also, each of the following structures of the specific examples is shownin the limited structural formula selected from several tautomerspossible in view of chemical structure. However, needless to say, thepigments may be in other tautomer structures than the descried ones.

The pigments of the invention represented by the general formulae (1),(3), and (4) to (7) may be in the form of the general formulae (1), (3),and (4) to (7) or may be the tautomers thereof, and may be of anycrystal forms called polymorphic forms.

Polymorphism means that crystals having the same chemical compositioncan be different from each other in the conformation of building block(molecules or ions) in the crystal. Chemical and physical properties ofthe pigments are decided by the crystal structure, and polymorphic formsof the same pigment can be discriminated from each other by rheology,color, and other color characteristics. Also, different polymorphicforms can be confirmed by X-Ray Diffration (results of powder X-raydiffractiometry) or by X-Ray Analysis (results of X-ray analysis ofcrystal structure).

In the case where the pigments of the invention represented by thegeneral formulae (1), (3), and (4) to (7) exhibit polymorphism, they maybe in any polymorphic forms and may be a mixture of two or morepolymorphic forms.

With those which have acid groups among the azo pigments of theinvention represented by the general formulae (1), (3), and (4) to (7),part or all of the acid groups may be in a salt form, or the pigment maybe a mixture of a salt type pigment and a free acid type pigment.Examples of the salt type include salts of an alkali metal such as Na,Li or K, salts of ammonium optionally substituted by an alkyl group or ahydroxyalkyl group, and salts of an organic amine. Examples of theorganic amine include a lower alkyl amine, a hydroxyl-substituted loweralkyl amine, a carboxy-substituted lower alkyl amine, and a polyaminehaving from 2 to 10 alkyleneimine units containing from 2 to 4 carbonatoms. With these salt type pigments, they are not necessarily limitedto one as to kind, but may be in a mixture of two or more thereof.

Further, as to the structure of the pigment to be used in the invention,in the case where plural acid groups exist in one molecule, the pluralacid groups may be of a salt type or an acid type, and may be differentfrom each other.

The azo pigments represented by the general formulae (1), (3), and (4)to (7) may be hydrates which contain water molecules within the crystal.

With the azo pigments of the invention represented, for example, by thegeneral formula (6), various tautomers and/or polymorphic fauns exist,and the azo pigments of different forms show, for example, differentabsorption patterns of IR absorption spectrum.

To illustrate this, two absorption patterns of IR absorption spectrumwith dye 2 are shown in FIGS. 1 and 2.

Absorption intensity in the range of from 1700 to 1730 cm⁻¹ is largelydifferent between the absorption pattern of FIG. 1 and the absorptionpattern of FIG. 2.

Hereinafter, crystals showing no absorption in the range between 1700and 1730 cm⁻¹ are referred to as type α, and crystals showing a strongabsorption in the range between 1700 and 1730 cm⁻¹ are referred to astype β.

Both of a pigment dispersion prepared by using an α-type azo pigment anda pigment dispersion prepared by using a β-type azo pigment are includedin the pigment dispersion of the invention. However, a pigmentdispersion prepared by using the α-type azo pigment shows betterdispersibility, thus being preferred.

The azo pigments represented by the general formula (1) can be producedaccording to the following process. That is, a heterocyclic aminerepresented by the following general formula (9) is diazotized;

Het.-NH₂  General formula (9):

wherein Het is the same as the heterocyclic group selected from thearomatic heterocyclic groups represented by the general formula (10),and * shows the point of attachment to the amino group in the generalformula (9),and subsequently the resulting diazonium is coupled with a compoundrepresented by the following general formula (11) to thereby produce anazo pigment represented by the general formula (1);

wherein each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom or a monovalent substituent, G represents the non-metallicatoms necessary to complete a 5- or 6-membered heterocyclic group, Wrepresents a substituent capable of binding to the heterocyclic groupconstituted by G, and t represents an integer of from 0 to 4.

In the general formula (9), Het is the same as Het-land Het-2 in thegeneral formula (1), and preferred examples thereof are also the same asdescribed there. The asterisk * shows the point of attachment to theamino group in the general formula (9).

In the general formula (11), R₁, R₂, P₁, P₂, Q₁, and Q₂ are the same asR₁, R₂, P₁, P₂, Q₁, and Q₂ in the general formula (1), and preferredexamples thereof are also the same as described there.

Examples of the substituent of G are the same as those of G in thegeneral formula (1), and preferred examples thereof are also the same asdescribed there.

Examples of the substituent W are the same as those of W in the generalformula (1), and preferred examples thereof are also the same asdescribed there.

Examples of t are the same as those of t in the general formula (1), andpreferred examples thereof are also the same as described there.

With respect to a preferred combination of the substituents in theintermediates of the pigment of the invention represented by the generalformulae (9) and (11), those compounds are preferred wherein at leastone of the various substituents is the preferred group having beendescribed hereinbefore, those compounds are more preferred wherein moreof the various substituents are the preferred groups having beendescribed hereinbefore, and those compounds are most preferred whereinall of the substituents are the preferred groups having been describedhereinbefore.

Particularly preferred combinations of the intermediates for the azopigments of the invention, represented by the general formulae (9) and(11), contain the following (a) to (k).

(a) G is preferably a 5- or 6-membered, nitrogen-containing heterocyclicgroup and, to illustrate without restricting the substitution positions,an s-triazine ring, a pyrimidine ring, a pyridazine ring, a pyrazinering, a pyridine ring, an imidazole ring, a pyrazole ring, and a pyrrolering are preferred. Of these, an s-triazine ring, a pyrimidine ring, apyridazine ring, and a pyrazine ring are preferred, with a2,3-pyridazine ring, a 2,4-pyrimidine ring, a 2,5-pyrazine ring, a2,6-pyrimidine ring, and an s-triazine ring being most preferred.(b) W is preferably a hydroxyl group, a cyano group, a substituted orunsubstituted carbamoyl group, a substituted or unsubstituted aminogroup, a substituted or unsubstituted alkoxy group, a substituted orunsubstituted aryloxy group, a substituted or unsubstituted alkylthiogroup, or a substituted or unsubstituted arylthio group, and a hydroxylgroup, a substituted or unsubstituted amino group, a substituted orunsubstituted alkoxy group, and a substituted or unsubstituted alkylthiogroup are particularly preferred, with a hydrogen atom, a hydroxylgroup, and an amino group being most preferred.(c) t represents an integer of from 0 to 4, preferably from 0 to 2, morepreferably 1 or 2, most preferably 1.(d) Preferably, each of R₁ and R₂ is independently a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing a total offrom 6 to 18 carbon atoms, or a substituted or unsubstitutedheterocyclic group containing a total of from 4 to 12 carbon atoms. Ofthem, a straight or branched alkyl group containing a total of from 1 to8 carbon atoms is preferred, and a methyl group and a sec- or tert-alkylgroup are preferred, with a methyl group and a t-butyl group being mostpreferred.(e) Preferably, each of P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom, a substituted or unsubstituted alkyl group, a substitutedor unsubstituted acyl group, a substituted or unsubstitutedalkylsulfonyl group, or a substituted or unsubstituted arylsulfonylgroup. Particularly preferred are a hydrogen atom, a substituted orunsubstituted alkyl group, and a substituted or unsubstituted acylgroup. Of them, a hydrogen atom is particularly preferred.(f) Preferably, each of Het-1 and Het-2 is independently selected fromthe aromatic heterocyclic groups (1) to (15) represented by theforegoing general formula (2). Of them, (1), (2), (3), (4), (5), (6),(7), (8), (9), (10), and (11) are preferred, (2), (5), (6), (7), (8),(9), and (10) are particularly preferred, (2), (5), (6), (7), and (10)are more preferred, and (2) and (7) are still more preferred, with (2)being most preferred.(g) Particularly preferred examples of X are a cyano group, analkylsulfonyl group containing from 1 to 12 carbon atoms, anarylsulfonyl group containing from 6 to 18 carbon atoms, and a sulfamoylgroup containing from 0 to 12 carbon atoms. Of them, a cyano group andan alkylsulfonyl group containing from 1 to 12 carbon atoms arepreferred, and a cyano group is most preferred.(h) Y is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group containing a total of from 1 to 12 carbon atoms, asubstituted or unsubstituted aryl group containing a total of from 6 to18 carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, and a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are particularly preferred, with ahydrogen atom being most preferred.(i) Z is preferably a hydrogen atom, a substituted or unsubstitutedalkyl group, a substituted or unsubstituted cycloalkyl group, asubstituted or unsubstituted alkenyl group, a substituted orunsubstituted alkynyl group, a substituted or unsubstituted aralkylgroup, a substituted or unsubstituted aryl group, or a substituted orunsubstituted heterocyclic group. Of them, a substituted orunsubstituted aryl group and a substituted or unsubstituted heterocyclicgroup are preferred, a substituted or unsubstituted heterocyclic groupis particularly preferred, and a substituted or unsubstituted,nitrogen-containing heterocyclic group is most preferred.(j) W₀ is particularly preferably a cyano group, an alkylsulfonyl groupcontaining from 1 to 12 carbon atoms, an arylsulfonyl group containingfrom 6 to 18 carbon atoms, or a sulfamoyl group containing from 0 to 12carbon atoms. Of them, a cyano group, a methanesulfonyl group, and aphenylsulfonyl group are preferred, with a cyano group being mostpreferred.(k) Each of W₁ to W₄ is preferably a hydrogen atom, a substituted orunsubstituted alkyl group containing a total of from 1 to 12 carbonatoms, a substituted or unsubstituted aryl group containing from 6 to 18carbon atoms, or a substituted or unsubstituted heterocyclic groupcontaining a total of from 4 to 12 carbon atoms. Of them, a hydrogenatom and a straight or branched alkyl group containing a total of from 1to 8 carbon atoms are preferred, a hydrogen atom and an alkyl groupcontaining from 1 to 8 carbon atoms are more preferred, and a hydrogenatom is most preferred.

Synthesis of the azo pigments of the invention will be described indetail below.

The azo pigments of the invention can be synthesized, for example, bycoupling reaction between a diazonium salt, prepared by diazotization ofa diazo component of the general formula (9) in a conventionally knownmanner, and a coupling component of the general formula (11).

Preparation of the Diazonium Salt and the Coupling Reaction can beConducted in a conventional manner.

In preparing the diazonium salt of the general formula (9), there can beapplied a conventional process for synthesizing a diazonium salt of thegeneral formula (9), for example, by using a nitrosonium ion source, forexample, nitrous acid, nitrous acid salt or nitrosylsulfuric acid in areaction medium containing an acid (for example, hydrochloric acid,sulfuric acid, phosphoric acid, acetic acid, propionic acid,methanesulfonic acid or trifluoromethanesulfonic acid).

As more preferred examples of the acid, there can be illustrated aceticacid, propionic acid, methanesulfonic acid, phosphoric acid, andsulfuric acid, which may be used alone or in combination thereof. Ofthese, a system containing phosphoric acid or a combination of aceticacid and sulfuric acid is particularly preferred.

As the reaction medium (solvent), organic acids and inorganic acids arepreferred to use. In particular, phosphoric acid, sulfuric acid, aceticacid, propionic acid, and methanesulfonic acid are preferred. Of them,acetic acid and/or propionic acid is preferred.

As to a preferred example of the nitrosonium ion source, use ofnitrosylsulfuric acid in a reaction medium containing theabove-mentioned preferred acid enables one to prepare the diazonium saltwith stability and efficiency.

The amount of the solvent to be used for the diazo component of thegeneral formula (9) is preferably a 0.5- to 50-fold amount by weight,more preferably a 1- to 20-fold amount by weight, particularlypreferably a 3- to 10-fold amount, based on the diazo component.

In the invention, the diazo component of the general formula (9) may bedispersed in the solvent, or may be in a state of solution dependingupon kind of the diazo component.

The amount of nitrosonium ion source to be used is preferably from 0.95to 5.0 equivalents, more preferably from 1.00 to 3.00 equivalents,particularly preferably from 1.00 to 1.10, based on the diazo component.

The reaction temperature is preferably from −15° C. to 30° C., morepreferably from −10° C. to 10° C., still more preferably from −5° C. to5° C. In case when the temperature is lower than −10° C., the reactionrate becomes so small that the synthesis takes a seriously prolongedperiod, thus such temperature not being economical. Also, in case whenthe synthesis is conducted at a high temperature exceeding 30° C.,amounts of by-products are increased, thus such temperature not beingpreferred.

The reaction time is preferably from 30 minutes to 300 minutes, morepreferably from 30 minutes to 200 minutes, still more preferably from 30minutes to 150 minutes.

The coupling reaction can be performed in an acidic to basic reactionmedium. With the azo pigments of the invention, the coupling reaction ispreferably performed in an acidic to neutral reaction medium. Inparticular, when the coupling reaction is performed in an acidicreaction medium, the diazonium salt can be converted to the azo pigmenteffectively with suppressing decomposition of the diazonium salt.

As preferred examples of the reaction medium (solvent), organic acids,inorganic acids, and organic solvents may be used, with organic solventsbeing particularly preferred. Those solvents are preferred which do notcause liquid separation phenomenon upon reaction but provide a uniformsolution. Examples thereof include alcoholic organic solvents such asmethanol, ethanol, propanol, isopropanol, butanol, t-butyl alcohol, andamyl alcohol; ketone series organic solvents such as acetone and methylethyl ketone; diol series organic solvents such as ethylene glycol,diethylene glycol, triethylene glycol, propylene glycol, dipropyleneglycol, and 1,3-propanediol; ether series organic solvents such asethylene glycol monomethyl ether, ethylene glycol monoethyl ether, andethylene glycol diethyl ether; tetrahydrofuran; dioxane; andacetonitrile. These solvents may be used as a mixed solution of two ormore thereof.

Preferred are organic solvents having a polar parameter (ET) of 40 ormore. Of them, glycol series solvents having two or more hydroxyl groupsin the solvent molecule and alcoholic solvents containing 3 or lesscarbon atoms, preferably 2 or less carbon atoms (for example, methanoland ethylene glycol) are preferred. Mixed solvents of these solvents arealso included.

The amount of the solvent to be used is preferably a 1- to 100-foldamount by weight, more preferably a 1- to 50-fold amount by weight,still more preferably a 2- to 10-fold amount by weight, based on thecoupling component represented by the general formula (11).

In the invention, the coupling component of the general formula (7) maybe dispersed in the solvent, or may be in a state of solution dependingupon kind of the coupling component.

The coupling component is to be used in such amount that the amount ofthe diazo component per azo-coupling position becomes preferably from0.95 to 5.0 equivalents, more preferably from 1.00 to 3.00 equivalents,particularly preferably from 1.00 to 1.50 equivalents.

The reaction temperature is preferably from −30° C. to 30° C., morepreferably from −15° C. to 10° C., still more preferably from −10° C. to5° C. In case when the temperature is lower than −30° C., the reactionrate becomes so small that the synthesis takes a seriously prolongedperiod, thus such temperature not being economical. Also, in case whenthe synthesis is conducted at a high temperature exceeding 30° C.,amounts of by-products are increased, thus such temperature not beingpreferred.

The reaction time is preferably from 30 minutes to 300 minutes, morepreferably from 30 minutes to 200 minutes, still more preferably from 30minutes to 150 minutes.

In the process of synthesizing the azo pigment of the invention, theproduct (crude azo pigment) obtained by these reactions can be usedafter subjecting the product to ordinary after-treatments of organicsynthesis reactions and subsequent purification or without purification.

That is, the product liberated from the reaction system can be usedwithout further purification or after purification procedures ofrecrystallization, salt formation, and the like, which may be conductedalone or in combination thereof.

It is also possible to remove, after completion of the reaction, thereaction solvent by distillation or, without distillation, pour thereaction product into water or ice-water, collect the liberated productafter or without neutralization, or extract the neutralized ornon-neutralized reaction solution with an organic solvent/an aqueoussolution, and conduct purification procedures of recrystallization,crystallization, salt formation, and the like, which procedures may beconducted alone or in combination of two or more thereof, thus obtaininga product for use.

The process for synthesizing the azo pigment of the invention will bedescribed in more detail below.

The process for synthesizing the azo pigment of the invention ischaracterized by conducting the coupling reaction between the diazoniumcompound prepared by diazotization of the heterocyclic amine representedby the general formula (9) and the compound represented by the generalformula (11) after dissolving the compound of the general formula (11)in an organic solvent.

The diazotization reaction of the heterocyclic amine represented by thegeneral formula (9) can be conducted, for example, by reacting it with areagent such as sodium nitrite or nitrosylsulfonic acid in an acidicsolvent such as sulfuric acid, phosphoric acid or acetic acid at atemperature of 15° C. or less for about 10 minutes to about 6 hours. Thecoupling reaction is preferably conducted by reacting the diazonium saltobtained by the above-mentioned process with the compound represented bythe general formula (11) at 40° C. or less, preferably 15° C. or less,for about 10 minutes to about 12 hours.

The tautomerism and the polymorphism can be controlled throughproduction conditions upon the coupling reaction. As a process forproducing more preferred α-form crystals, for example, the process ofthe invention is preferred wherein the compound represented by thegeneral formula (11) is once dissolved in an organic solvent, and thenthe coupling reaction is conducted. As the organic solvent which can beused in this reaction, there are illustrated, for example, alcoholsolvents. Preferred examples of the alcohol solvents include methanol,ethanol, isopropanol, ethylene glycol, and diethylene glycol. Of these,methanol is particularly preferred.

Another process for producing the azo pigment of the invention ischaracterized in that, in the coupling reaction between the diazoniumcompound prepared by diazotization of the heterocyclic amine representedby the general formula (9) and the compound represented by the generalformula (11), the coupling reaction is conducted in the presence of apolar aprotic solvent.

The α-form crystals can also be effectively produced by the process ofconducting the coupling reaction in the presence of the polar aproticsolvent. Examples of the polar aprotic solvent includeN,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,dimethylsulfoxide, tetramethylurea, and a mixed solvent thereof. In thecase of using these solvents, the compound of the general formula (11)may or may not be completely dissolved.

The compounds represented by the general formulae (1), (3), and (4) to(7) are obtained as crude azo pigments by the above-mentioned productionprocesses. In the case of using them as the pigments of the invention,they are preferably subjected to after-treatment. As methods of theafter-treatment, there are illustrated, for example, a pigmentparticle-controlling step such as milling treatment (e.g., solvent-saltmilling, salt milling, dry milling, solvent milling or acid pasting) orsolvent heating treatment; and a surface-treating step using, forexample, a resin, a surfactant or a dispersing agent.

The compounds of the invention represented by the general formulae (1),(3), and (4) to (7) are preferably subjected to the solvent heatingtreatment and/or the solvent-salt milling as the after-treatment.

As a solvent to be used in the solvent heating treatment, there areillustrated, for example, water, aromatic hydrocarbon series solventssuch as toluene and xylene; halogenated hydrocarbon series solvents suchas chlorobenzene and o-dichlorobenzene; alcoholic solvents such asisopropanol and isobutanol; polar aprotic organic solvents such asN,N-dimethylformamide, N,N-dimethylacetamide, andN-methyl-2-pyrrolidone; glacial acetic acid; pyridine; and a mixturethereof. An inorganic or organic acid or base may further be added tothe above-described solvents. The temperature of the solvent heatingtreatment varies depending upon the desired primary particle size of thepigment, but is preferably from 40 to 150° C., more preferably from 60to 100° C. The treating time is preferably from 30 minutes to 24 hours.

As the solvent-salt milling, there is illustrated the procedure whereina crude azo pigment, an inorganic salt, and an organic solvent whichdoes not dissolve them are placed in a kneader, and knead-milling of themixture is conducted therein. As the inorganic salt, water-solubleinorganic salts can preferably be used. For example, inorganic saltssuch as sodium chloride, potassium chloride, and sodium sulfate arepreferably used. Also, it is more preferred to use inorganic saltshaving an average particle size of from 0.5 to 50 μm. The amount of theinorganic salt to be used is preferably a 3- to 20-fold amount byweight, more preferably a 5- to 15-fold amount by weight, based on thecrude pigment. As the organic solvent, water-soluble organic solventscan preferably be used and, since the solvent becomes easily vaporizedue to an increase in temperature upon kneading, high-boiling solventsare preferred in view of safety. Examples of such organic solventsinclude diethylene glycol, glycerin, ethylene glycol, propylene glycol,liquid polyethylene glycol, liquid polypropylene glycol,2-(methoxymethoxy)ethanol, 2-butoxyethanol, 2-(isopentyloxy)ethanol,2-(hexyloxy)ethanol, diethylene glycol monomethyl ether, diethyleneglycol monoethyl ether, diethylene glycol monobutyl ether, triethyleneglycol, triethylene glycol monomethyl ether, 1-methoxy-2-propanol,1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethylether, dipropylene glycol monomethyl ether, dipropylene glycol, and amixture thereof. The amount of the water-soluble organic solvent to beused is preferably a 0.1- to 5-fold amount based on the crude azopigment. The kneading temperature is preferably from 20 to 130° C.,particularly preferably from 40 to 110° C. As a kneader, there can beused, for example, a kneader and a mix muller.

[Pigment Dispersion]

The pigment dispersion of the invention is characterized in that itcontains at least one of the azo pigments represented by the generalformulae (1), (3), and (4) to (7). Thus, there can be obtained a pigmentdispersion having excellent coloring characteristics, durability, anddispersion stability.

The pigment dispersion of the invention may be aqueous or non-aqueous,but is preferably an aqueous pigment dispersion. As the aqueous liquidfor dispersing the pigment in the aqueous pigment dispersion of theinvention, a mixture containing water as a major component and, asneeded, a hydrophilic organic solvent can be used. Examples of thehydrophilic organic solvent include alcohols such as methanol, ethanol,propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol,pentanol, hexanol, cyclohexanol, and benzyl alcohol; polyhydric alcoholssuch as ethylene glycol, diethylene glycol, triethylene glycol,polyethylene glycol, propylene glycol, dipropylene glycol, polypropyleneglycol, butylenes glycol, hexanediol, pentanediol, glycerin,hexanetriol, and thiodiglycol; glycol derivatives such as ethyleneglycol monomethyl ether, ethylene glycol monoehyl ether, ethylene glycolmonobutyl ether, diethylene glycol monomethyl ether, diethylene glycolmonobutyl ether, propylene glycol monomethyl ether, propylene glycolmonobutyl ether, dipropylene glycol monomethyl ether, triethylene glycolmonomethyl ether, ethylene glycol diacetate, ethylene glycol monomethylether acetate, triethylene glycol monomethyl ether, and ethylene glycolmonophenyl ether; amines such as ethanolamine, diethanolamine,triethanolamine, N-methyldiethanolamine, N-ethyl diethanolamine,morpholine, N-ethylmorpholine, ethylenediamine, diethylenetriamine,triethylenetetramine, polyethyleneimine, andtetramethylpropylenediamine; formamide; N,N-dimethylformamide;N,N-dimethylacetamide; dimethylsulfoxide; sulfolane; 2-pyrrolidone;N-methyl-2-pyrrolidone; N-vinyl-2-pyrolidone; 2-oxazolidone;1,3-dimethyl-2-imidazolidinone; acetonitrile; and acetone.

Further, the aqueous pigment dispersion of the invention may contain anaqueous resin. As the aqueous resin, there are illustrated water-solubleresins which dissolve in water, water-dispersible resins which can bedispersed in water, colloidal dispersion resins, and a mixture thereof.Specific examples of the aqueous resins include acryl series resins,styrene-acryl series resins, polyester resins, polyamide resins,polyurethane resins, and fluorine-containing resins.

Further, in order to improve dispersibility of the pigment and qualityof image, a surfactant and a dispersing agent may be used. As thesurfactant, there are illustrated anionic, nonionic, cationic, andamphoteric surfactants, and any of them may be used. However, anionic ornonionic surfactants are preferred to use. Examples of the anionicsurfactants include aliphatic acid salts, alkyl sulfate salts,alkylbenzene sulfonate salts, alkylnaphthalene sulfonate salts, dialkylsulfosuccinate salts, alkyldiaryl ether disulfonate salts, alkylphosphate salts, polyoxyethylene alkyl ether sulfate salts,polyoxyethylene alkylaryl ether sulfate salts, naphthalenesulfonicacid-formalin condensates, polyoxyethylene alkyl phosphatesalts,glycerol borate fatty acid esters, and polyoxyethylene glycerol fattyacid esters.

Examples of the nonionic surfactants include polyoxyethylene alkylethers, polyoxyethylene alkylaryl ethers, polyoxyethylene-ooxypropyleneblock copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitanfatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerinfatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylenealkylamines, fluorine-containing surfactants, and silicon-containingsurfactants.

The non-aqueous pigment dispersion comprises the pigment represented bythe general formula (1) dispersed in a non-aqueous vehicle. Examples ofresin to be used as the vehicle include petroleum resin, casein,shellac, rosin-modified maleic acid resin, rosin-modified phenol resin,nitrocellulose, cellulose acetate butyrate, cyclized rubber, chlorinatedrubber, oxidized rubber, rubber hydrochloride, phenol resin, alkydresin, polyester resin, unsaturated polyester resin, amino resin, epoxyresin, vinyl resin, vinyl chloride, vinyl chloride-vinyl acetatecopolymer, acryl resin, methacryl resin, polyurethane resin, siliconeresin, fluorine-containing resin, drying oil, synthetic drying oil,styrene/maleic acid resin, styrene/acryl resin, polyamide resin,polyimide resin, benzoguanamine resin, melamine resin, urea resin,chlorinated polypropylene, butyral resin, anc vinylidene chloride resin.It is also possible to use a photo-curable resin as the non-aqueousvehicle.

Examples of the solvents to be used in the non-aqueous vehicles includearomatic solvents such as toluene, xylene, and methoxybenzene; acetateseries solvents such as ethyl acetate, butyl acetate, propylene glycolmonomethyl ether acetate, and propylene glycol monoethyl ether acetate;propionate series solvents such as ethoxyethyl propionate; alcoholicsolvents such as methanol and ethanol; ether series solvents such asbutyl cellosolve, propylene glycol monomethyl ether, diethylene glycolethyl ether, and diethylene glycol dimethyl ether; ketone seriessolvents such as methyl ethyl ketone, methyl isobutyl ketone, andcyclohexanone; aliphatic hydrocarbon series solvents such as hexane;nitrogen-containing compound series solvents such asN,N-dimethylformamide, γ-butyrolactam, N-methyl-2-pyrrolidone, aniline,and pyridine; lactone series solvents such as γ-butyrolactone; andcarbamic acid esters such as a 48:52 mixture of methyl carbamate andethyl carbamate.

The pigment dispersion of the invention is obtained by dispersing theazo pigment and the aqueous or non-aqueous medium using a dispersingapparatus. As the dispersing apparatus, there can be used a simplestirrer, an impeller-stirring system, an in-line stirring system, a millsystem (for example, colloid mill, ball mill, sand mill, beads mill,attritor, roll mill, jet mill, paint shaker or agitator mill), aultrasonic wave system, a high-pressure emulsion dispersion system(high-pressure homogenizer; specific commercially available apparatusesbeing Gaulin homogenizer, a microfluidizer, and DeBEE2000).

In the invention, the volume-average particle size of the pigment ispreferably from 10 nm to 250 nm. Additionally, the volume-averageparticle size of the pigment particles means the particle size of thepigment particle itself or, in the case where an additive such as adispersing agent is adhered to the coloring material, the particle sizeof the pigment particle to which the additive is adhered. In theinvention, a nanotrac UPA particle size distribution analyzer(UPA-EX150; manufactured by Nikkiso Co., Ltd.) was used as a measuringapparatus for measuring the volume-average particle size of the pigment.The measurement was performed according to the predetermined method byplacing 3 ml of a pigment dispersion in a measuring cell. Additionally,as to parameters to be inputted upon measurement, ink viscosity was usedas the viscosity, and pigment density was used as the density ofdispersed particles.

The volume-average particle size is more preferably from 20 nm to 250nm, still more preferably from 30 nm to 230 nm, and most preferably from30 nm to 150 nm. In case where the volume-average particle size of theparticles in the pigment dispersion is less than 20 nm, storagestability of the dispersion might not be ensured in some cases whereas,in case where the size exceeds 250 nm, there might result a low opticaldensity in some cases.

The concentration of the pigment contained in the pigment dispersion ofthe invention is in the range of preferably from 1 to 35% by weight,more preferably from 2 to 25% by weight. In case where the concentrationis less than 1% by weight, an enough image density might not be obtainedwhen the pigment dispersion is singly used as an ink. In case where theconcentration exceeds 35% by weight, there might result a reduceddispersion stability in some cases.

As uses of the azo pigments of the invention, there are illustratedimage recording materials for forming images, particularly color images.Specifically, there are illustrated inkjet system recording materials tobe described in detail below, heat-sensitive recording materials,pressure-sensitive recording materials, recording materials for theelectro-photographic system, transfer system silver halidelight-sensitive materials, printing inks, and recording pens, preferablyinkjet system recording materials, heat-sensitive recording materials,and recording materials for the electro-photographic system, morepreferably inkjet system recording materials.

In addition, the pigments can find application to color filters forrecording and reproducing color images to be used in solid state imagingdevices such as CCDs and in displays such as LCD and PDP and to apigmenting solution for pigmenting various fibers.

The bisazo pigments of the invention are used by adjusting physicalproperties such as solvent resistance, dispersibility, and heatconductivity through selection of the substituents so as to be adaptedfor the particular use. Also, the bisazo pigments of the invention maybe used in an emulsion dispersion state or in a solid dispersion stateaccording to the system wherein they are used.

[Coloring Composition]

The coloring composition of the invention means a coloring compositioncontaining at least one kind of the azo pigments of the invention. Thecoloring composition of the invention can contain a medium and, in thecase where a solvent is used as the medium, the composition isparticularly appropriate as an ink for inkjet recording. The coloringcomposition of the invention can be prepared by using an oleophilicmedium or an aqueous medium as the medium and dispersing the azo pigmentof the invention in the medium. Preferably, the aqueous medium is used.The coloring composition of the invention includes an ink compositionexcluding the medium. The coloring composition of the invention maycontain, as needed, other additives within the range of not spoiling theadvantages of the invention. Examples of the other additives includeknown additives (described in JP-A-2003-306623) such as adrying-preventing agent (a wetting agent), an antifading agent, anemulsion stabilizer, a penetration accelerator, an ultraviolet rayabsorbent, an antiseptic, an antifungal agent, a pH-adjusting agent, asurface tension-adjusting agent, an anti-foaming agent, aviscosity-adjusting agent, a dispersing agent, a dispersion stabilizer,a rust inhibitor, and a chelating agent. In the case of water-solubleinks, these various additives are added directly to the ink solution. Inthe case of oil-soluble inks, it is general to add to a dispersion afterpreparing the azo pigment dispersion, but they may be added to an oilphase or an aqueous phase upon preparation.

[Ink]

Next, the ink of the invention will be described below.

The ink of the invention contains the pigment dispersion of theinvention described above and is preferably prepared by mixing with awater-soluble solvent or water. However, in the case where no particularproblems are involved, the pigment dispersion of the invention describedabove may be used as such.

The ink of the invention for inkjet recording contains the pigmentdispersion of the invention, and can also be used as an ink for inkjetrecording.

Also, the coloring composition containing the pigment of the inventioncan preferably be used as an ink for inkjet recording.

The ink of the invention uses the pigment dispersion described above,and is preferably prepared by mixing with a water-soluble solvent orwater. However, in the case where no particular problems are involved,the pigment dispersion of the invention described above may be used assuch.

The ink of the invention uses the pigment dispersion described above,and is preferably prepared by mixing with a water-soluble solvent orwater. However, in the case where no particular problems are involved,the pigment dispersion of the invention described above may be used assuch.

[Ink for Inkjet Recording]

Next, the ink of the invention for inkjet recording will be describedbelow.

The ink of the invention for inkjet recording (hereinafter in some casesreferred to as “ink”) uses the pigment dispersion described above, andis preferably prepared by mixing with a water-soluble solvent or water.However, in the case where no particular problems are involved, thepigment dispersion of the invention described above may be used as such.

In view of hue, color density, saturation, and transparency of an imageformed on a recording medium, the content of the pigment dispersion inthe ink of the invention is in the range of preferably from 1 to 100% byweight, particularly preferably from 3 to 20% by weight, most preferablyfrom 3 to 10% by weight.

The pigment of the invention is contained in an amount of from 0.1 partby weight to 20 parts by weight, more preferably from 0.2 part by weightto 10 parts by weight, still more preferably from 1 to 10 parts byweight, in 100 parts by weight of the ink of the invention. The ink ofthe invention may further contain other pigment in combination with thepigment of the invention. In the case of using two or more kinds ofpigments, the total amount of the pigments is preferably within theabove-described range.

The ink of the invention can be used for forming a full-color image aswell as a mono-color image. In order to form the full-color image, amagenta tone ink, a cyan tone ink, and a yellow tone ink can be usedand, further, a black tone ink can be used for adjusting tone.

Further, in the ink of the invention may be used other pigments inaddition to the azo pigment of the invention. As yellow pigments to beapplied, there are illustrated, for example, C.I. PY-74, C.I. PY-128,C.I. PY-155, C.I. PY-213. As magenta pigments to be applied, there areillustrated C.I. PV-19 and C.I. PR-122. As cyan pigments to be applied,there are illustrated C.I. PB-15:3 and C.I. PB-15:4. Apart from thesepigments, any pigment may be used as each pigment. As a black colormaterial, there can be illustrated a carbon black dispersion as well asdisazo, trisazo, and tetrazo pigments.

As the water-soluble solvents to be used in the ink of the invention,polyhydric alcohols, polyhydric alcohol derivatives, nitrogen-containingsolvents, alcohols, and sulfur-containing solvents are used.

Specific examples of the polyhydric alcohols include ethylene glycol,diethylene glycol, propylene glycol, butylenes glycol, triethyleneglycol, 1,5-pentanediol, 1,2,6-hexanetriol, and glycerin.

Examples of the polyhydric alcohol derivatives include ethylene glycolmonomethyl ether, ethylene glycol monoethyl ether, ethylene glycolmonobutyl ether, diethylene glycol monomethyl ether, diethylene glycolmonoethyl ether, diethylene glycol monobutyl ether, propylene glycolmonobutyl ether, dipropylene glycol monobutyl ether, and an ethyleneoxide adduct of diglycerin.

Also, examples of the nitrogen-containing solvents include pyrrolidone,N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, and triethanolamine,examples of the alcohols include ethanol, isopropyl alcohol, butylalcohol, and benzyl alcohol, and examples of the sulfur-containingsolvents include thiodiethanol, thiodiglycerol, sulfolane, anddimethylsulfoxide. Besides, propylene carbonate and ethylene carbonatemay also be used.

The water-soluble solvents to be used in the invention may be used aloneor as a mixture of two or more thereof. As to the content of thewater-soluble solvent, the solvent is used in an amount of from 1% byweight to 60% by weight, preferably from 5% by weight to 40% by weight,based on the total weight of the ink. In case where the content of thewater-soluble solvent in the entire ink is less than 1% by weight, theremight result an insufficient optical density in some cases whereas, incase where the content exceeds 60% by weight, there might resultunstable jet properties of the ink liquid in some cases due to the largeviscosity of the liquid.

The preferred physical properties of the ink of the invention are asfollows.

The surface tension of the ink is preferably from 20 mN/m to 60 mN/m,more preferably from 20 mN/m to 45 mN/m, still more preferably from 25mN/m to 35 mN/m. In case where the surface tension is less than 20 mN/m,the liquid might, in some cases, overflow onto the nozzle surface of therecording head, thus normal printing not being performed. On the otherhand, in case where the surface tension exceeds 60 mN/m, the ink might,in some cases, slowly penetrate into the recording medium, thus thedrying time becoming longer.

Additionally, the surface tension was measured under the environment of23° C. and 55% RH by using a Wilhelmy surface tension balance in thesimilar manner to above.

The viscosity of the ink is preferably from 1.2 mPa·s to 8.0 mPa·s, morepreferably from 1.5 mPa·s to 6.0 mPa·s, still more preferably from 1.8mPa·s to 4.5 mPa·s. In case where the viscosity is more than 8.0 mPa·s,ink ejection properties might, in some cases, be deteriorated. On theother hand, in case where the viscosity is less than 1.2 mPa·s, thelong-term ejection properties might be deteriorated in some cases.

Additionally, the viscosity (including that to be described hereinafter)was measured by using a rotational viscometer Rheomat 115 (manufacturedby Contraves Co.) at 23° C. and a shear rate of 1,400 s⁻¹.

In addition to the above-mentioned individual components, water is addedto the ink within an amount of providing the preferred surface tensionand viscosity described above. The addition amount of water is notparticularly limited, but is in the range of preferably from 10% byweight to 99% by weight, more preferably from 30% by weight to 80% byweight, based on the total weight of the ink.

Further, for the purpose of controlling characteristic properties suchas improvement of ejection properties, there can be used, as needed,polyethyleneimine, polyamines, polyvinylpyrolidone, polyethylene glycol,cellulose derivatives such as ethyl cellulose and carboxymethylcellulose, polysaccharides and derivatives thereof, water-solublepolymers, polymer emulsions such as an acrylic polymer emulsion, apolyurethane series emulsion, and a hydrophilic latex, hydrophilicpolymer gels, cyclodextrin, macrocyclic amines, dendrimers, crownethers, urea and derivatives thereof, acetamide, silicone surfactants,and fluorine-continuing surfactants.

Also, in order to adjust electrical conductivity and pH, there can beused compounds of alkali metals such as potassium hydroxide, sodiumhydroxide, and lithium hydroxide; nitrogen-containing compounds such asammonium hydroxide, triethanolamine, diethanolamine, ethanolamine, and2-amino-2-methyl-1-propanol; compounds of alkaline earth metals such ascalcium hydroxide; acids such as sulfuric acid, hydrochloric acid, andnitric acid; and salts between a strong acid and a weak alkali, such asammonium sulfate.

Besides, pH buffers, antioxidants, antifungal agents,viscosity-adjusting agents, electrically conductive agents, andultraviolet ray absorbents may also be added as needed.

[Inkjet Recording Method, Inkjet Recording Apparatus, and Ink Tank forInkjet Recording]

The inkjet recording method of the invention is a method of forming animage on a recording medium by using the ink of the invention for inkjetrecording, and ejecting the ink onto the surface of the recording mediumthrough the recording head according to recording signals.

Also, the inkjet recording apparatus of the invention is an apparatusfor forming an image, which is equipped with a recording head capable ofejecting the ink of the invention for inkjet recording (a processingsolution as needed) onto the surface of a recording medium, with the inkbeing ejected onto the surface of the recording medium through therecording head to form an image. Additionally, in the inkjet recordingapparatus of the invention, the recording head may be equipped with anink tank for inkjet recording which can feed the ink to the recordinghead and is removable from the body of the inkjet recording apparatus(hereinafter in some cases referred to as “ink tank”). In this case, theink of the invention is retained in the ink tank for inkjet recording.

As the inkjet recording apparatus of the invention, a common inkjetrecording apparatus, which is equipped with a printing system capable ofusing the ink of the invention for inkjet recording, can be utilized.Besides, there may be used, as needed, an apparatus on which a heaterfor controlling drying is further mounted or an apparatus on which anintermediate transferring mechanism is further mounted and in which theink and a processing solution are ejected (printed) onto an intermediatetransfer member and are then transferred to a recording medium such aspaper.

Also, as the ink tank of the invention for inkjet recording, aconventionally known ink tank may be utilized as long as it can beremovably mounted on an inkjet recording apparatus equipped with arecording head and has such constitution that the ink can be fed to therecording head.

As to the inkjet recording method (apparatus) of the invention, it ispreferred to employ a thermal inkjet recording system or a piezoelectricinkjet recording system in view of reducing feathering and inter-colorbleed.

In the case of the thermal inkjet recording system, the ink is heatedupon ejection to decrease the viscosity of the ink. Since thetemperature of the ink decreases on the recording medium, the viscosityrapidly increases to afford the effect of reducing feathering andinter-color bleed. On the other hand, in the case of the piezoelectricinkjet recording system, ejection of a highly viscous liquid, which isable to suppress spreading of the liquid in the paper surface directionon the recording medium, is possible, thus the effect of reducingfeathering and inter-color bleed being obtained.

In the inkjet recording method (apparatus) of the invention, the ink ispreferably replenished (fed) to a recording head from an ink tank(including a processing solution tank) that is filled with the ink. Thistank is preferably a cartridge that can be removably attached to thebody of the apparatus, and the ink is easily replenished by changing theink tank cartridge.

[Color Toner]

The content of the bisazo pigment of the invention in 100 parts byweight of the color toner of the invention is not particularly limited,but is preferably 0.1 part by weight or more, more preferably from 1 to20 parts by weight, most preferably from 2 to 10 parts by weight. As abinder resin for color toner to be used for introducing the bisazopigment of the invention, all binders that are generally used can beused. Examples thereof include styrene series resins, acryl seriesresins, styrene/acryl series resins, and polyester resins.

Inorganic fine powders and organic fine particles may externally beadded to a toner for the purpose of improving fluidity and controllingcharging properties. Silica fine particles and titania fine particles,whose surface has been treated with a coupling agent containing an alkylgroup, are preferably used. Additionally, these particles preferablyhave a number-average primary particle size of from 10 to 500 nm, andare added to the toner in an amount of preferably from 0.1 to 20% byweight.

As a releasing agent, all releasing agents that have conventionally beenused can be used. Specifically, there are illustrated olefins such aslow-molecular-weight polypropylene, low-molecular-weight polyethylene,and ethylene-propylene copolymer; microcrystalline wax; carnauba wax;sazol wax; and paraffin wax. The addition amount of the releasing agentis preferably from 1 to 5% by weight in the toner.

As a charge-controlling agent which may optionally be added, colorlessones are preferred in view of color-forming properties. For example,there are illustrated those with a quaternary ammonium salt structureand those with a calix arene structure.

As a carrier, either of non-coated carriers constituted only byparticles of a magnetic material such as iron or ferrite andresin-coated carriers comprising magnetic material particles coated witha resin may be used. The average particle size of the carrier ispreferably from 30 to 150 μm in terms of volume average particle size.

The image-forming method to which the toner of the invention is appliedis not particularly limited, but is exemplified by a method whereincolor images are repeatedly formed on a photoreceptor, and then thecolor images are transferred to form an image, and a method wherein animage formed on a photoreceptor is transferred every time to anintermediate transfer member to form a color image on the intermediatetransfer member, and then the color image is transferred to animage-forming member such as paper to form a color image.

[Heat-Sensitive Recording (Transfer) Material]

The heat-sensitive recording material is constituted by an ink sheetcomprising a support having provided thereon a layer containing thebisazo pigment of the invention and a binder; and an image-receivingsheet for immobilizing the pigment migrating corresponding to the heatenergy added from a thermal head according to image-recording signals.The ink sheet can be formed by dispersing the bisazo pigment of theinvention in a solvent together with the binder to prepare an inkliquid, coating this ink liquid on the support, and properly drying thecoated ink liquid. The coated amount of the ink on the support is notparticularly limited, but is preferably from 30 to 1,000 mg/m². As topreferred binder resins, ink solvents, supports, and image-receivingsheets, those described in JP-A-7-137466 can preferably be used.

In order to apply the heat-sensitive recording material to aheat-sensitive recording material which can record a full-color colorimage, it is preferred to form a cyan ink sheet containing aheat-diffusible cyan colorant capable of forming a cyan image, a magentaink sheet containing a heat-diffusible magenta colorant capable offorming a magenta image, and a yellow ink sheet containing aheat-diffusible yellow colorant capable of forming a yellow image, bycoating on a sheet. In addition, an ink sheet containing a black colorimage-forming substance may further be formed as needed.

[Color Filter]

As a method for forming a color filter, there are a method of firstforming a pattern by using a photoresist, and then dyeing it, and amethod of forming a pattern by a photoresist having added thereto acolorant as described in JP-A-4-163552, JP-A-4-128703, andJP-A-4-175753. As a method to be employed in the case of introducing thecolorant of the invention into a color filter, either one of thesemethods may be employed. However, as a preferred method, there can beillustrated a method for forming a color filter described inJP-A-4-175753 and JP-A-6-35182, which comprises using a positive resistcomposition containing a thermosetting resin, a quinonediazide compound,a cross-linking agent, a colorant, and a solvent, coating thiscomposition on a substrate, exposing through a mask, developing theexposed areas to thereby form a positive resist pattern, exposing theentire surface of the positive resist pattern, and then curing theexposed positive resist pattern. Also, a color filter in the system ofRGB primary colors or YMC complementary colors can be obtained byforming a black matrix in a conventional manner. With the color filter,too, the amount of the bisazo pigment of the invention is not limited,but is preferably from 0.1 to 50% by weight.

As the thermosetting resin, quinonediazide compound, cross-linkingagent, solvent, and the amounts thereof to be used, those which aredescribed in the aforesaid patent literature can preferably be used.

EXAMPLES

The invention will be described in more detail by reference to Exampleswhich, however, are not to be construed as limiting the invention.Additionally, in Examples, “parts” are by weight.

Example 1 Synthesis of Illustrative Pigment (Pig-1)

3.7 Parts of 5-amino-3-methyl-1,2,4-thiazole is added to 45 parts ofphosphoric acid, and heated to 38° C. to dissolve. This solution iscooled with ice-water to keep the solution at −3° C., 2.5 parts ofsodium nitrite is added thereto, and the mixture is stirred for 1.5hours to obtain a diazonium salt solution. Separately, 4 parts of thecompound represented by the following formula (13) is added to 80 partsof N,N-dimethylacetamide to prepare a completely dissolved solution. Theabove-described diazonium salt solution is added thereto at 8° C. Thesolution is kept in this state for 2 hours to react. After increasingthe temperature of the solution to room temperature, 100 parts ofethanol is added thereto, and a precipitated powder is collected byfiltration. This powder is added to 200 parts of water, and excess acidis neutralized with sodium hydrogen carbonate. Filtration is againconducted to obtain a yellow powder. This yellow powder is added to amixed solvent of 40 parts of N,N-dimethylacetamide and 40 parts ofwater, followed by heating at 100° C. for 4 hours to ripen. Thethus-ripened solution is hot filtered and washed with methanol to obtain4.8 parts of the azo pigment.

The infrared absorption spectrum of the thus-obtained azo pigment(Pig-1) is shown in FIG. 1. In the case of conducting the synthesisaccording to the above-described process, the product shows noabsorption peak in the range of from 1700 to 1730 cm⁻¹ in the infraredabsorption spectrum.

Example 2 Synthesis of Illustrative Pigment (Pig-2)

Diazotization reaction of 5-amino-3-methyl-1,2,4-thiadiazole isconducted in the same manner as in Example 1. Separately, 4 parts of thecompound represented by the above formula (13) is added to 80 parts ofmethanol to suspend. To this suspension is added the above-mentioneddiazonium salt solution at 8° C. The reaction was continued as it is for2 hours and precipitated powder is collected by filtration. This powderis added to 200 parts of water, and excess acid is neutralized withsodium hydrogen carbonate. Filtration is again conducted to obtain aslightly reddish yellow powder. This powder is added to a mixed solventof 40 parts of N,N-dimethylacetamide and 40 parts of water, followed byheating at 100° C. for 4 hours to ripen. The thus-ripened solution ishot filtered and washed with methanol to obtain 6.4 parts of the azopigment. The infrared absorption spectrum of the thus-obtained azopigment (Pig-2) is shown in FIG. 2. In the case of conducting thesynthesis according to the above-described process, the product shows alarge absorption peak in the range of from 1700 to 1730 cm⁻¹ in theinfrared absorption spectrum.

Example 3 Synthesis of Illustrative Pigment (Pig-4)

1.6 Parts of 5-amino-1,2,4-thiazole is added to 20 parts of phosphoricacid, and heated to 38° C. to dissolve. This solution is cooled withice-water to keep the solution at −3° C., 1.4 parts of sodium nitrite isadded thereto, and the mixture is stirred for 1.5 hours to obtain adiazonium salt solution. Separately, 2 parts of the compound representedby the above formula (13) is added to 200 parts of methanol to prepare acompletely dissolved solution. The above-described diazonium saltsolution is added thereto at 5° C. The solution is kept in this statefor 4 hours to react, and a precipitated powder is collected byfiltration. This powder is added to 200 parts of water, and excess acidis neutralized with sodium hydrogen carbonate. Filtration is againconducted to obtain a yellow powder. This yellow powder is added to amixed solvent of 10 parts of N,N-dimethylacetamide and 10 parts ofwater, followed by heating at 100° C. for 4 hours to ripen. Thethus-ripened solution is hot filtered and washed with methanol to obtain0.9 part of the azo pigment. The infrared absorption spectrum of thethus-obtained azo pigment (Pig-4) is shown in FIG. 3.

Example 4 Synthesis of Illustrative Pigment (Pig-7)

1.8 Parts of 5-amino-3-methyl-1,2,4-thiazole is added to 22 parts ofphosphoric acid, and heated to 38° C. to dissolve. This solution iscooled with ice-water to keep the solution at −3° C., 1.3 parts ofsodium nitrite is added thereto, and the mixture is stirred for 1.5hours to obtain a diazonium salt solution. Separately, 1.5 parts of thecompound represented by the following formula (14) is added to 30 partsof N,N-dimethylformamide to prepare a suspension. The above-describeddiazonium salt solution is added thereto at 5° C. The solution is keptin this state for 7 hours to react. 40 Parts of methanol is addedthereto, and a precipitated powder is collected by filtration. Thispowder is added to 200 parts of water, and excess acid is neutralizedwith sodium hydrogen carbonate. Filtration is again conducted to obtaina yellow powder. This yellow powder is added to 30 parts ofN,N-dimethylacetamide, followed by heating at 100° C. for 4 hours toripen. The thus-ripened solution is hot filtered and washed with acetoneto obtain 1.9 parts of the azo pigment.

The infrared absorption spectrum of the thus-obtained azo pigment(Pig-7) is shown in FIG. 4.

Example 5 Synthesis of Illustrative Pigment (Pig-27)

2.1 Parts of 5-amino-4-cyano-1-phenylpyrazole is added to a mixedsolution of 5.1 parts of concentrated sulfuric acid, 22.8 parts ofglacial acetic acid, and 2.1 parts of nitrosylsulfuric acid at 4° C. Themixture is stirred in this state for 1 hour to obtain a diazonium saltsolution. Separately, 1.5 parts of the compound represented by thefollowing formula (14) is added to 45 parts of N,N-dimethylacetamide toprepare a suspension. The above-described diazonium salt solution isadded thereto at 5° C. The solution is kept in this state for 6 hours toreact. After increasing the temperature of the solution to roomtemperature, 60 parts of methanol is added thereto, and a precipitatedpowder is collected by filtration. This powder is added to 200 parts ofwater, and excess acid is neutralized with sodium hydrogen carbonate.Filtration is again conducted to obtain a yellow powder. This yellowpowder is added to 30 parts of N,N-dimethylacetamide, followed byheating at 100° C. for 4 hours to ripen. The thus-ripened solution ishot filtered and washed with acetone to obtain 0.9 part of the azopigment. The infrared absorption spectrum of the thus-obtained azopigment (Pig-27) is shown in FIG. 5.

Example 6 Synthesis of Illustrative Pigment (Pig-47)

2.5 Parts of 2-amino-5-methyl-1,3,4-thiadiazole is added to 30 parts ofphosphoric acid, and heated to 42° C. to dissolve. This solution iscooled with ice-water to keep the solution at −3° C., 1.7 parts ofsodium nitrite is added thereto, and the mixture is stirred for 1.5hours to obtain a diazonium salt solution. Separately, 2.9 parts of thecompound represented by the following formula (13) is added to 60 partsof N,N-dimethylacetamide to prepare a completely dissolved solution. Theabove-described diazonium salt solution is added thereto at 5° C. Thesolution is kept in this state for 3 hours to react. A precipitatedpowder is collected by filtration. This powder is added to 200 parts ofwater, and excess acid is neutralized with sodium hydrogen carbonate.Filtration is again conducted to obtain a yellow powder. This yellowpowder is added to a mixed solvent of 25 parts of N,N-dimethylacetamideand 25 parts of water, followed by heating at 100° C. for 4 hours toripen. The thus-ripened solution is hot filtered and washed withmethanol to obtain 2.6 parts of the azo pigment. The infrared absorptionspectrum of the thus-obtained azo pigment (Pig-47) is shown in FIG. 6.

Examples 7 to 31

According to the procedures described in the above detailed descriptionon synthesis of the azo pigments of the invention and Examples 1 to 6,the illustrative pigments (Pig-9), (Pig-11), (Pig-12), (Pig-13),(Pig-16), (Pig-25), (Pig-28), (Pig-29), (Pig-30), (Pig-31), (Pig-32),(Pig-37), (Pig-39), (Pig-41), (Pig-42), (Pig-43), (Pig-44), (Pig-45),(Pig-46), (Pig-49), (Pig-51), (Pig-52), (Pig-53), (Pig-54) and (Pig-59)are synthesized. The infrared absorption spectra of the thus-obtainedazo pigments are shown in FIGS. 7 to 31.

Example 41

2.5 Parts of the pigment (Pig-1) synthesized in Example 1, 0.5 part ofsodium oleate, 5 parts of glycerin, and 42 parts of water are mixed, andsubjected to dispersing procedure together with 100 parts of zirconiabeads of 0.1 mm in diameter at 300 rpm for 6 hours using a planetaryball mill. After completion of the dispersing procedure, the zirconiabeads are separated to obtain a yellow pigment dispersion 1.

Example 42

5 Parts of the pigment (Pig-1) synthesized in Example 1, 25.5 parts ofan aqueous solution of a high-molecular dispersant of methacrylicacid-methacrylic acid ester copolymer represented by Dispersant Solution10 which is described in WO2006/064193, p. 22, and 19.5 parts of waterare mixed, and subjected to dispersing procedure together with 100 partsof zirconia beads of 0.1 mm in diameter at 300 rpm for 6 hours using aplanetary ball mill. After completion of the dispersing procedure, thezirconia beads are separated to obtain a yellow pigment dispersion 2.

Examples 43 to 49

In the same procedures as in Example 41 except for using (Pig-24),(Pig-26), (Pig-46), (Pig-32), (Pig-70), (Pig-80) and (Pig-59) in placeof the pigment (Pig-1) used in Example 41, there is obtained a yellowpigment dispersions 3, 4, 5, 6, 7, 8, and 9 respectively.

Examples 50 to 55

In the same procedures as in Example 41 except for using (Pig-4),(Pig-6), (Pig-47), (Pig-49), (Pig-51), (Pig-52) in place of the pigment(Pig-1) used in Example 41, there is obtained a yellow pigmentdispersions 10, 11, 12, 13, 14 and 15 respectively.

Examples 56 to 60

In the same procedures as in Example 41 except for using (Pig-7),(Pig-9), (Pig-11), (Pig-12) and (Pig-13) in place of the pigment (Pig-1)used in Example 41, there is obtained a yellow pigment dispersions 16,17, 18, 19 and 20 respectively.

In the same procedures as in Example 41 except for using (Pig-16),(Pig-17) and (Pig-18) in place of the pigment (Pig-1) used in Example41, there is obtained a yellow pigment dispersions 21, 22 and 23respectively.

Comparative Example 1

In the same procedures as in Example 41 except for using C.I. PigmentYellow 128 (manufactured by Ciba Specialty Co.; CROMOPHTAL YELLOW 8GN)in place of the pigment (Pig-1) used in Example 41, there is obtained ayellow comparative pigment dispersion 1.

Comparative Example 2

In the same procedures as in Example 41 except for using C.I. PigmentYellow 74 (manufactured by Ciba Specialty Co.; halite YELLOW GO) inplace of the pigment (Pig-1) used in Example 41, there is obtained ayellow comparative pigment dispersion 2.

Comparative Example 3

In the same procedures as in Example 41 except for using C.I. PigmentYellow 155 (manufactured by Clariant Co.; INKJET YELLOW 4G VP2532) inplace of the pigment (Pig-1) used in Example 41, there is obtained ayellow comparative pigment dispersion 3.

Comparative Example 4

It is tried to prepare a yellow comparative pigment dispersion 4 in thesame procedures as in Example 41 except for using a comparative compound1 of the structure described below in place of the pigment (Pig-1) usedin Example 41, but the colorant is dissolved in the solvent to form asolution of the colorant, and a dispersion of fine particles is notobtained.

Comparative Example 5

It is tried to prepare a yellow comparative pigment dispersion 5 in thesame procedures as in Example 41 except for using a comparative compound2 of the structure described below in place of the pigment (Pig-1) usedin Example 41, but the colorant is dissolved in the solvent to form asolution of the colorant, and a dispersion of fine particles is notobtained.

<Evaluation of Coloring Strength>

Each of the pigment dispersions obtained in Examples and ComparativeExamples is coated on a photo mat paper (to be used exclusively forpigments) manufactured by Seiko Epson Corporation by using a No. 3 barcoater. Image density of each of the thus-obtained coated products ismeasured by means of a reflection densitometer (X-Rite 938; manufacturedby X-Rite Co.), and the results are shown in Table 1 as “coloringstrength (OD: Optical Density).

<Evaluation of Hue>

Hue is evaluated according to the following criteria: samples of theabove-described products which are less greenish and have largevividness in terms of chromaticity when viewed with the eye are ranked A(good); samples which are greenish or have less vividness are ranked B;and samples which are greenish and have less vividness are ranked C(bad). The results are shown in Table 1.

<Evaluation of Light Fastness>

Each of the coated products of 1.0 in image density used in evaluationof hue is irradiated for 7 days with a xenon light (170,000 lux; in thepresence of a cut filter which cuts light of 325 nm or less) and imagedensity thereof is measured before and after irradiation with the xenonlight using a reflection densitometer. The pigment dispersions 1 to 23of the invention and the comparative pigment dispersions 1 to 5 areevaluated in terms of colorant residual ratio [(density afterirradiation/density before irradiation)×100%]. Samples with a colorantresidual ratio of 90% or more are ranked A, samples with a colorantresidual ratio of 80% or more are ranked B, samples with a colorantresidual ratio of 70% or more are ranked C, samples with a colorantratio of 60% or more are ranked D, and samples with a colorant ratio ofless than 50% are ranked E. The results are shown in Table 1.

<Solvent Resistance>

0.05 part of each of the compounds used in Examples and Comparativeexamples is added to 200 parts of an organic solvent and is allowed tostand for 24 hours. The thus-prepared samples are evaluated. Evaluationis conducted according to the following criteria: samples with which thecompounds of Examples or Comparative examples are completely dissolvedin the organic solvent are ranked D; samples with which the compoundsare not completely dissolved with leaving insolubles, but filtratesthereof are colored are ranked C; samples with which the compounds arenot completely dissolved with leaving insolubles, but filtrates thereofare slightly colored are ranked B; and samples with which insolublesremain and filtrates are not colored are ranked A. Additionally, as theorganic solvent, a mixture of 25 parts of methanol, 25 parts of acetone,25 parts of ethyl acetate, and 25 parts of water is used as a mixedsolvent.

TABLE 1 Volume-average Coloring Light Solvent Pigment DispersionParticle Size Strength Hue Fastness Resistance Example 41 pigmentdispersion 1 of Mv: about 55 nm 1.35 B B B the invention Example 42pigment dispersion 2 of Mv: about 35 nm 1.33 B B B the invention Example43 pigment dispersion 3 of Mv: about 50 nm 1.40 A C B the inventionExample 44 pigment dispersion 4 of Mv: about 53 nm 1.40 A C B theinvention Example 45 pigment dispersion 5 of Mv: about 70 nm 1.37 B C Bthe invention Example 46 pigment dispersion 6 of Mv: about 60 nm 1.37 BA A the invention Example 47 pigment dispersion 7 of Mv: about 50 nm1.35 B A A the invention Example 48 pigment dispersion 8 of Mv: about 58nm 1.35 B B A the invention Example 49 pigment dispersion 9 of Mv: about56 nm 1.39 B C A the invention Example 50 pigment dispersion 10 of Mv:about 56 nm 1.33 B C B the invention Example 51 pigment dispersion 11 ofMv: about 58 nm 1.36 B B B the invention Example 52 pigment dispersion12 of Mv: about 60 nm 1.33 B C B the invention Example 53 pigmentdispersion 13 of Mv: about 65 nm 1.39 B B B the invention Example 54pigment dispersion 14 of Mv: about 61 nm 1.41 B B B the inventionExample 55 pigment dispersion 15 of Mv: about 64 nm 1.40 B B B theinvention Example 56 pigment dispersion 16 of Mv: about 58 nm 1.36 B C Bthe invention Example 57 pigment dispersion 17 of Mv: about 60 nm 1.34 BB B the invention Example 58 pigment dispersion 18 of Mv: about 54 nm1.34 B C B the invention Example 59 pigment dispersion 19 of Mv: about63 nm 1.35 B C B the invention Example 60 pigment dispersion 20 of Mv:about 68 nm 1.34 B C B the invention Example 61 pigment dispersion 21 ofMv: about 55 nm 1.34 B B C the invention Example 62 pigment dispersion22 of Mv: about 56 nm 1.38 B C B the invention Example 63 pigmentdispersion 23 of Mv: about 54 nm 1.33 B C B the invention Comparativecomparative pigment Mv: about 50 nm 1.03 C C A Example 1 dispersion 1Comparative comparative pigment Mv: about 50 nm 1.43 A E B Example 2dispersion 2 Comparative comparative pigment Mv: about 45 nm 1.09 C D AExample 3 dispersion 3 Comparative comparative pigment Fine particle — —— D Example 4 dispersion 4 dispersion not being formed Comparativecomparative pigment Fine particle — — — D Example 5 dispersion 5dispersion not being formed

Example 64

The high-molecular dispersant represented by Dispersant 10 and describedin WO2006/064193, page 22 is neutralized with an aqueous solution ofpotassium hydroxide. 30 Parts by weight of the azo pigment (Pig-1)synthesized in Example 1 and 95 parts by weight of deionized water areadded to 75 parts by weight of the thus-obtained dispersant aqueoussolution (solid content: 20%), and mixed and coarsely dispersed with adisper agitating member. 600 Parts by weight of zirconia beads are addedto the mixed and coarsely dispersed solution, and dispersed in adispersing machine (sand grinder mill) for 4 hours, followed byseparating the dispersion from the beads. To the thus-obtained mixtureis gradually added 2 parts by weight of polyethylene glycol diglycidylether at 25° C. under stirring, and the mixture is stirred at 50 C for 6hours. Further, impurities are removed by using an ultrafiltrationmembrane of 300K in molecular cutoff, and the resulting dispersion isfiltered through a 20-ml volume syringe fit with a filter having a poresize of 5 μm (acetylcellulose membrane; outer diameter: 25 mm;manufactured by Fuji Photo Film Co., Ltd.) to remove coarse particles.Thus, a pigment dispersion 24 containing 10% solid components (averageparticle size: Mv=about 55 nm; measured by using Nanotrac 150(UPA-EX150) manufactured by Nikkiso Co., Ltd.) is obtained.

Comparative Example 6

A comparative pigment dispersion 6 is obtained in the same manner as inExample 64 except for using a yellow pigment (C.I. Pigment Yellow 128(CROMOPHTAL YELLOW 8GN manufactured by Ciba Specialty Co.) in place ofthe azo pigment (Pig-1) used in Example 64.

Example 65

Individual components are added so that the content of the pigmentdispersion 24 obtained in Example 64 is 5% by weight, the content ofglycerin is 10% by weight, the content of 2-pyrrolidone is 5% by weight,the content of 1,2-hexanediol is 2% by weight, the content oftriethylene glycol monobutyl ether is 2% by weight, the content ofpropylene glycol is 0.5% by weight, and the content of deionized wateris 75.5% by weight. The thus-obtained mixed solution is filtered througha syringe fit with a filter having a pore size of 1 μm (acetylcellulosemembrane; outer diameter: 25 mm; manufactured by Fuji Photo Film Co.,Ltd.) to remove coarse particles. Thus, a pigment ink liquid 1 shown inTable 2 is obtained.

Comparative Example 7

A comparative pigment ink liquid 1 is obtained in the same manner as inExample 65 except for using the comparative pigment dispersion 6obtained in Comparative Example 6 in place of the pigment dispersion 24obtained in Example 64.

The ink liquids obtained in Example 65 and Comparative Example 7 areused as yellow pigment ink liquids.

Comparative Example 8

Also, as a comparative ink type, a yellow ink cartridge (comparativepigment ink liquid 2) of PX-V630 manufactured by Epson Co. is used.

Additionally, in Table 2, with respect to “ejection stability”, “lightfastness”, “heat fastness”, “ozone (gas) resistance”, “metal gloss”,“chromaticity”, and “ink liquid stability”, each ink is filled in ayellow ink cartridge of an inkjet printer PX-V630 manufactured by SeikoEpson Corporation, inks of PX-V630 are used for other color inks, and ayellow mono-color pattern with the density being stepwise changed and animage pattern comprising green, red, and gray are printed on animage-receiving sheet, i.e., photographic paper <Kotaku> manufactured bySeiko Epson Corporation or photographic paper CRISPIA <Ko-kotaku>manufactured by Seiko Epson Corporation with the recommended mode“Kirei” to evaluate image quality, ink ejection properties, and imagefastness.

The ink liquid of Example 65 (pigment ink liquid 1) and the comparativeink liquids of Comparative Examples (comparative pigment ink liquid 1and yellow pigment ink liquid of PX-V630, i.e., comparative pigment inkliquid 2) for use in inkjet recording are subjected to the followingevaluations. The results are shown in Table 2.

(Evaluation Experiments)

1) As for the ejection stability, after setting the cartridge in theprinter and confirming the ejection of ink from all nozzles, the imagepattern is outputted on 20 sheets of A4-size paper and rated based onthe following criteria.

A: Printing is not disordered from start through end of the printing.

B: Printing is disordered in some outputs.

C: Printing is disordered from start through end of the printing.

2) As for the yellow image preservability, the following evaluations areconducted by using a printed sample.[1] In the evaluation of light fastness, the image density Ciimmediately after printing is measured by X-rite 310, the image is thenirradiated with xenon light (100,000 lx) for 35 days by the use ofWeathermeter made by Atlas, and the image density Cf is again measured.The yellow image residual ratio Cf/Ci×100 is determined and evaluated.The yellow image residual ratio is evaluated at three points each havinga reflection density of 1, 1.5, and 2, and the light fastness is rated Awhen the yellow image residual ratio is 80% or more at any density,rated B when less than 80% at two points, or rated C when less than 80%at all points.[2] In the evaluation of heat fastness, the density is measured byX-rite 310 before and after the sample is stored for 14 days under theconditions of 80° C. and 60% RH, and the yellow image residual ratio isdetermined and evaluated. The yellow image residual ratio is evaluatedat three oints each having a reflection density of 1, 1.5, and 2, andthe heat fastness is rated A when the yellow image residual ratio is 95%or more at any density, rated B when less than 95% at two points, orrated C when less than 95% at all densities.[3] In the evaluation of ozone resistance (ozone fastness), the sampleis left standing for 35 days in a box set to an ozone gas concentrationof 5 ppm (23° C., 50%), and the image density before and after standingin the ozone gas atmosphere is measured by a reflection densitometer(Photographic Densitometer 310; manufactured by X-Rite) and evaluated asthe yellow image residual ratio. The reflection density is measured atthree points of 1, 1.5, and 2.0. The ozone gas concentration in the boxis set by using an ozone gas monitor (Model: OZG-EM-01) manufactured byAPPLICS. The ozone resistance is rated on a three-stage scale, namely,rated A when the yellow image residual ratio is 80% or more at anydensity, rated B when less than 80% at one or two points, or rated Cwhen less than 70% at all densities.3) Occurrence or non-occurrence of metal gloss: The yellow, green, andred solid printed image portions are visually observed by reflectedlight, and evaluated.

Samples with non-occurrence of metal gloss are evaluated as A, andsamples with occurrence of metal gloss are evaluated as B.

4) Chromaticity: A yellow mono-coor image pattern with a stepwisechanging density is measured for CIE L*a*b* by Spectro Eye manufacturedby Gretag Macbeth. The a* and the b* at a reflection density of 1.0 areshown in the following table. As the image-receiving sheet, photographicpaper CRISPIA <Ko-kotaku> manufactured by Seiko Epson Corporation isused.5) Ink liquid stability: Each of the pigment ink liquids of Examples andComparative Examples is allowed to stand at 60° C. for 10 days. Samplesundergoing no change in the particle size of particles in the pigmentink liquids are rated A, samples undergoing change in the particle sizeare rated B. The results are shown in Table 2 below.

TABLE 2 Ink Ejection Light Heat Ozone Metal Chroma- Chroma- Liquid InkStability Fastness Fastness Fastness Gloss ticity a* ticity b* StabilityPigment Example 52 A A A A A −8.52 75.79 A Pig-1 (present invention)Comparative A B A A B −9.33 61.15 A C.I. Example 7 PY-128 Comparative AC A A A −11.97 73.68 A PX-V630 Example 8

It is seen from the results of Table 2 that the pigment ink liquid usingthe pigment of the invention shows excellent ink-ejecting properties andexcellent weatherability, undergoes less occurrence of metal gloss,shows excellent hue as yellow (a* being minus which means lessreddishness, and b* being large which means high saturation), and hasexcellent pigment ink liquid stability.

As is apparent from the results in Table 2, it can be seen that thesystem wherein the ink of the invention is used is excellent in allperformances. In particular, in comparison with Comparative Examples,the ink of the invention has excellent light fastness and excellent inkliquid stability.

Example 66

An image is printed on an inkjet paper of photo gloss paper “Gasai”manufactured by Fuji Photo Film Co., Ltd. by means of PX-V630manufactured by Seiko Epson Corporation using the pigment ink liquidprepared in Example 65, and is evaluated in the same manner as inExample 65 to obtain similar results.

As is apparent from the results in Tables 1 and 2, the pigmentdispersions 1 to 23 using the pigments of the invention and the pigmentink liquid 1 using the pigment of the invention are excellent in colortone and show high coloring strength and light resistance.

Accordingly, the pigment dispersions using the pigments of the inventioncan preferably be used in an ink for printing such as inkjet printing, acolor toner for electrophotography, a color filter to be used fordisplays such as LCD and PDP and photographing devices such as CCD, apaint, and in colored plastics.

INDUSTRIAL APPLICABILITY

According to the invention, there are provided azo pigments havingexcellent coloring characteristics such as coloring ability and hue andhaving excellent durability such as light fastness and resistance toozone. A pigment dispersion, a coloring composition, and an ink for inkjet recording, having excellent coloring characteristics, durability,and dispersion stability, can be obtained by dispersing the pigment ofthe invention in various media. The pigment dispersion can be used foran ink for printing such as ink jet printing, a color toner forelectrophotography, a display such as LCD or PDP, a color filter to beused in photographing equipment such as CCD, a paint, a colored plastic,etc.

The entire disclosure of each and every foreign patent application fromwhich the benefit of foreign priority has been claimed in the presentapplication is incorporated herein by reference, as if fully set forth.

1. An azo pigment represented by the following general formula (1), atautomer of the azo pigment, and a salt or a hydrate thereof:

wherein each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom or a substituent, G represents the non-metallic atomsnecessary to complete a 5- to 6-membered heterocyclic group, Wrepresents a substituent capable of binding to the heterocyclic groupconstituted by G, t represents an integer of from 0 to 4, each of Het-1and Het-2 independently represents a group selected from the aromaticheterocyclic groups represented by the following general formula (2):

wherein each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄ independently representsa hydrogen atom or a substituent, and * shows the point of attachment tothe azo linkage in the general formula (1).
 2. The azo pigment, thetautomer of the azo pigment, and the salt or hydrate thereof accordingto claim 1, wherein the azo pigment is represented by the followinggeneral formula (3):

wherein each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, G represents the non-metallic atoms necessary to complete a5- to 6-membered heterocyclic group, W represents a substituent capableof binding to the heterocyclic group constituted by G, t represents aninteger of from 0 to 4, each of Het-1 and Het-2 independently representsa group selected from aromatic heterocyclic groups represented by thegeneral formula (2), provided that * in the general formula (2) showsthe point of attachment to the azo linkage in the general formula (3).3. The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to claim 1, wherein the azo pigment isrepresented by the following general formula (4):

wherein each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, each of X₁ and X₂ independently represents anelectron-withdrawing group having a Hammett's σp value of 0.2 or more,each of Y₁, Y₂, Z₁, and Z₂ independently represents a hydrogen atom or asubstituent, G represents the non-metallic atoms necessary to complete a5- to 6-membered heterocyclic group, W represents a substituent capableof binding to the heterocyclic group constituted by G, and t representsan integer of from 0 to
 4. 4. The azo pigment, the tautomer of the azopigment, and the salt or hydrate thereof according to claim 1, whereinthe azo pigment is represented by the following general formula (5):

wherein each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, each of Het-1 and Het-2 independently represents a groupselected from the aromatic heterocyclic groups represented by thegeneral formula (2), provided that * in the general formula (2) showsthe point of attachment to the azo linkage in the general formula (5),and W represents a substituent on the s-triazinyl group.
 5. The azopigment, the tautomer of the azo pigment, and the salt or hydratethereof according to claim 1, wherein the azo pigment is represented bythe following general formula (6):

wherein each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, and each of Het-1 and Het-2 independently represents agroup selected from the aromatic heterocyclic groups represented by thegeneral formula (2), provided that * in the general formula (2) showsthe point of attachment to the azo linkage in the general formula (6).6. The azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof according to claim 1, wherein the tautomer of the azopigment is represented by any one of the following general formulae (6′)to (6′″):

wherein each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, and each of Het-1 and Het-2 independently represents agroup selected from the aromatic heterocyclic groups represented by thegeneral formula (2), provided that * in the general formula (2) showsthe point of attachment to the azo linkage in the general formulae (6′)to (6′″).
 7. The azo pigment, the tautomer of the azo pigment, and thesalt or hydrate thereof according to claim 1, wherein the azo pigmenthas a peak absorption intensity in the range of from 1700 to 1730 cm⁻¹in the IR absorption spectrum which is 1/3 or less of a peak absorptionintensity in the range of from 1620 to 1670 cm⁻¹.
 8. The azo pigment,the tautomer of the azo pigment, and the salt or hydrate thereofaccording to claim 1, wherein the azo pigment is represented by thefollowing general formula (7):

wherein each of R₁ and R₂ independently represents a hydrogen atom or asubstituent, each of X₁ and X₂ independently represents anelectron-withdrawing group having a Hammett's σp value of 0.2 or more,each of Y₁, and Y₂ independently represents a hydrogen atom or asubstituent, G₁ represents the non-metallic atoms necessary to completea 5- to 6-membered heterocyclic group, W represents a substituentcapable of binding to the heterocyclic group constituted by G₁, trepresents an integer of from 0 to 4, each of G₁₁ and G₁₂ independentlyrepresents the non-metallic atom groups necessary to complete a 5- to6-membered heterocyclic group, provided that each of the heterocyclicgroups represented by G₁₁ and G₁₂ may independently be unsubstituted ormay have a substituent, and may be a monocyclic ring or may have acondensed ring.
 9. The azo pigment, the tautomer of the azo pigment, andthe salt or hydrate thereof according to claim 8, wherein at least oneof the nitrogen-containing heterocyclic groups respectively representedby G₁₁ and G₁₂ is represented by any one of (G-1) to (G-13) in thefollowing general formula (8):

wherein * in (G-1) to (G-13) shows the point of attachment to the N atomon the pyrazole ring in the general formula (7), each of Z₁₁ to Z₁₄represents a substituent capable of binding to the heterocyclic group,and G′ in (G-13) represents the non-metallic atoms necessary to completea heterocyclic group.
 10. A process for producing the azo pigmentdescribed in claim 1, comprising: preparing a diazonium compound bydiazotization of a heterocyclic amine represented by the followinggeneral formula (9), dissolving a compound represented by the followingformula (11) in an organic solvent, and coupling the diazonium compoundand the compound represented by the general formula (11) after thedissolution of the compound represented by the general formula (11):Het.-NH₂  General formula (9) wherein Het. represents a heterocyclicgroup selected from aromatic heterocyclic groups represented by thefollowing general formula (10):

wherein each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄ independently representsa hydrogen atom or a substituent, and * shows the point of attachment tothe amino group in the general formula (9):

wherein each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom or a substituent, G represents the non-metallic atomsnecessary to complete a 5- to 6-membered heterocyclic group, Wrepresents a substituent capable of binding to the heterocyclic groupconstituted by G, and t represents an integer of from 0 to
 4. 11. Aprocess for producing the azo pigment described in claim 1, comprising:preparing a diazonium compound by diazotization of a heterocyclic aminerepresented by the following general formula (9), coupling the diazoniumcompound and a compound represented by the following general formula(11) in the presence of a polar aprotic solvent:Het.-NH₂  General formula (9) wherein Het. represents a heterocyclicgroup selected from aromatic heterocyclic groups represented by thefollowing general formula (10):

wherein each of X, Y, Z, W₀, W₁, W₂, W₃, and W₄ independently representsa hydrogen atom or a substituent, and * shows the point of attachment tothe amino group in the general formula (9):

wherein each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom or a substituent, G represents the non-metallic atomsnecessary to complete a 5- to 6-membered heterocyclic group, Wrepresents a substituent capable of binding to the heterocyclic groupconstituted by G, and t represents an integer of from 0 to
 4. 12. Theazo pigment represented by the following general formula (1), which isobtained by the process described in claim 10:

wherein each of R₁, R₂, P₁, P₂, Q₁, and Q₂ independently represents ahydrogen atom or a substituent, G represents the non-metallic atomsnecessary to complete a 5- to 6-membered heterocyclic group, Wrepresents a substituent capable of binding to the heterocyclic groupconstituted by G, t represents an integer of from 0 to 4, each of Het-1and Het-2 independently represents a group selected from the aromaticheterocyclic groups represented by the following general formula (2):

wherein each of X, Y, Z, W₀, W₁, W₂, W₃ and W₄ independently representsa hydrogen atom or a substituent, and * shows the point of attachment tothe azo linkage in the general formula (1).
 13. A pigment dispersioncomprising: at least one of the azo pigment, the tautomer of the azopigment, and the salt or hydrate thereof described in claim
 1. 14. Acoloring composition comprising: at least one of the azo pigment, thetautomer of the azo pigment, and the salt or hydrate thereof describedin claim
 1. 15. An ink for inkjet recording, comprising: at least one ofthe azo pigment, the tautomer of the azo pigment, and the salt orhydrate thereof described in claim 1.